For --The word translated as "for" introduces a reason or explanation so "because" and, in questions, "why." However, since this word always appears in the second position, it is more like an aside remark like, "consequently" or "as a cause." 

missing "the"  -- (MW) The untranslated word is the Greek definite article, which usually precedes a noun and, without a noun, takes the meaning of "the one." The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," "those"). See this article for more. 

God -- The word translated as "God" means "God" and "deity." It is introduced with an article, so "the God," "the Divine" or "the divine one." Jesus often uses it this way perhaps to indicate the one God as opposed to the pagan gods.

so  -- The word translated in KJV as "so" is in its adverbial form, so it means "in this manner" or "in this way." It also means "so much."

loved . -- (CW) The word translated as "love" expresses a lot of different ideas including "to be fond of," "to greet with affection," "to persuade," and "to be contented with." Jesus however, applies it to relationships where we have a duty to care for others: family, God, etc. Another word, also translated as "love" is used to for relationships of affectionate friendship that are more voluntary. To distinguish this word, translated it as "cares for" seems to work best. See this article on love for more information.

the -- The word translated as "the" is the Greek definite article, without a noun, it has the sense of "the one." The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," "those") than the English "the." See this article for more. 

world, -- Jesus uses the word translated as "the world" to mean "the world order," and "civilization," specifically its "rulers," or its organization. Today, we use the word "society" or "regime" in this sense. More about this word in this article about related words.

that -- (CW) "That" is an adverb that marks the power or virtue by which one does a thing, "as being," "inasmuch as," expresses the actual or intended result of the action in the principal clause: "as," "for," implying " on condition that," at the beginning of a sentence, to mark a strong conclusion, "and so," "therefore," and with subj. " in order that." It is not the simple, much more common word simple meaning "that."

he -- This is from the third-person, singular form of the verb.

gave -- The verb translated as "gave" means "to give," "to grant," "to hand over," "appoint," "establish," and "to describe." It is almost always translated as some form of "give."

his -- (IW) There is nothing in the Greek that can be translated as "his" in the Greek source.

missing "the/this"  -- (MW) The untranslated word is the Greek definite article,"the," which usually precedes a noun and, without a noun, takes the meaning of "the one." The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," "those"). See this article for more. 

one and only - - The term translated as "one and only" more generally it means "unique" and "singular."  It means literally "only born." In grammar, it also means a word having the same form in all genders, and it is kind of funny that the word itself a monogenic word, having the same form in all genders.

missing "the/this"  -- (MW) The untranslated word is the Greek definite article,"the," which usually precedes a noun and, without a noun, takes the meaning of "the one." The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," "those"). See this article for more. 

Son, -- The word translated as "son" more generally means "child" or "children." It can refer to all offspring in later generations, just like "father" refers to all previous generations. Jesus also used it metaphorically to describe those who follow a way of thought or set of beliefs that descend from an individual. More about it in this article.

that -- The word translated as "that" is an adverb "in that place," "there," "where," "when," or as a conjunction that starts a subordinate clause  "that," "when," "in order that" or "because." This is the common word meaning "that," not the same word as the one above.

whoever -- (CW) The word translated as "whoever" is the Greek adjective meaning "all," "the whole," "every," and similar ideas. When it is used as a noun, we would say "everything." As an adverb, it means "in every way," "on every side," and "altogether." Here it is single, "every one."

believes -- (WF) The Greek word translated as "believes" does not apply to religious belief as much as it does trusting in other people, especially their word. Christ usually uses it in contexts, as the one here, that apply to trusting words. The negation of "belief" with the objective, instead of subjective, negative, equates trust with a fact. The word is not an active verb but an participle, "trusting."

in --  (WW) The word translated as "in" means "into" a place, "towards" as a direction, "in regards to" a subject, and "up to" limits in time and measure. None of this fit that well, but it also means "as much as (of measure or limit)," and that meaning does fit with a person.

him - The word translated as "him" is the Greek word commonly translated as third-person pronouns in English. 

shall -- (WW) This helping verb in English comes from the form of the Greek verb that indicates a possibility and is not the future tense. We would usually say "might" or "should" in English.

not  - - The negative  "not" used here is the Greek negative of a subjective opinion, commands, and requests. The sense is that "you don't want" to do something, not that it isn't done or don't think something that might be true. If it wasn't done or wasn't true, the objective negative of fact would be used. The sense here is that the person doesn't "want" to cease to exist.

perish,  -  -  The word translated as ".perish" means "to cease to exist." The form is one of possibility not the future tense. With the negative used, the sense is "might not want to cease to exist." This seems in indicate that those who do not trust in him do not want to continue to exist. The sense is that not trusting in his promise equates to no trusting in a continued life and having access to it. The form is a word that acts on itself as we say "destroy himself."

missing "himself"  -- (MW) The verb is the Greek middle voice that indicates that subjects act "for" or "on" themselves.  Some English transitive verbs require a reflexive pronoun ("itself," "themselves" etc.) after the verb to capture this meaning.

but -- The Greek word translated as "but" denotes an exception or simple opposition. It is used to emphasize the contrast between things like we use "rather." It is the Greek word "other" like we use "otherwise." Jesus often uses this conjunction to connect a negative clause, not doing something, with a positive one, "instead do this."

have -- The word translated as "have" means to "have," "possess," "bear," "keep close," "have means to do,"  "to have due to one," or "keep" and many specific uses. This verb isn't used to form past tenses as it is in English. 

everlasting  - "Everlasting" is an adjective based on the word that means "age" or "eon." It has the sense of "perpetual" or "ageless."

life. - The word translated as "life" means "living" but it also means "substance," "existence," and "property." Christ uses it to mean "existence" beyond physical life. See this article on the various Greek words that Jesus uses to describe various aspects of life.