But -- The Greek word translated as "and" means "but," "however," and "on the other hand." It joins phrases in an adversarial way. Since it always falls in the second position, translating it as "however" often captures its feeling better. 

while - This comes from the form of the participle, departing followed by "them. This is called a
genitive absolute, a concept preceded by a "while."

they  - The word translated as "they" here is the Greek word commonly translated as pronouns in English, but the form is genitive, forming the subject of the genitive absolute.

were on their way - "Were on their way " is from a Greek verb that means "to go away," "to depart from," "to spread abroad," and "to depart from life." It is in the present tense in the form of an adjective "going way," but the play on words here is the subtle reference to dying like "departing" in English. Though it is a particle, it can be translated as an active verb in a "while" phrase as part of the genitive absolute.

to -- This "to" is added because the infinitive form of the verb requires a "to" in English.

buy, The word translated as "to buy" comes from the noun form of the word for "marketplace," which means "to occupy a marketplace," "to buy in the market," and "to occupy a marketplace." It is something like the way we uses "shop" as the verb form of "to shop."

the oil, -- (IP) There is nothing that can be translated as "the oil" in the Greek source.

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. 

bridegroom  - The word translated as "bridegroom" is a male form of the adjective meaning "bridal," hence, "groom" or, if plural, "the wedding couple." This was the person who plays a central role in a celebration, or, as we would say, "a celebrity." The point is that he is the one who can get the girls into the party.

arrived;  -- The word translated as "arrived" primarily means "to start out" but Christ usually uses it to mean "come" but not always. It indicates movement, especially its beginning, without indicating a direction toward or away from anything, so it works either as "start," "come," or "go," but it is more like our phrase "being underway." Our English word "show up" captures both the "start" and "come" ideas. See this article for more.

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. 

virgins -- (IW) There is nothing that can be translated as "that were" in the Greek source. There is no verb here at all.

who were -- (IW) There is nothing that can be translated as "who were" in the Greek source. There is no verb here at all.

ready  - "Ready" is from a noun that means "at hand," "ready," "prepared," of persons, "ready," "active," "zealous," of the mind, "ready," "bold."

went in  - "Went in" is from a word that means "go or come into" and has the double meaning of "coming into one's mind."

with   -- "With" is the Greek word that usually means "with" or a related concept such as "among" or "by the means of."

him - The word translated as "him" here is the Greek word commonly translated as pronouns in English,

to -- The word translated as "to" means "into" a place, "towards" as a direction, "in regards to" a subject, and "up to" limits in time and measure.

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. 

wedding banquet:  - The Greek word translated as "wedding banquet" is from a verb that means "marriage," "wedding," and "wedlock." Weddings were the "parties" and "celebrations" of Christ's era. Virtually no other events, not birthdays or anniversaries, were celebrated in the same way.

and -- The Greek word translated as "and" is used as the conjunction "and," but it also is used to add emphasis ("also").

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. 

door  - The word translated as "the door" means "door," and "gate," and, metaphorically, "entrance to the soul."

was -- This helping verb "was" indicates that the verb is passive. Helping or auxiliary verbs are needed to translate the Greek verb forms into English.

shut.  - The word translated as "shut" is an entertaining bit of wordplay. It is a verb that means "to close" or "to shut in," but, in this form, it is also the a similar form of another verb that means "to make famous" and "to celebrate in song." The word used for "shut" here is used twice previously. In Matthew 6:6, Christ tells us to pray to God secretly with the door shut behind us. In Matthew 23:13, Christ uses the same term to describe the sin of the scribes and Pharisees: shutting up the kingdom of heaven by requiring too much of regular people.