πενθεῖν [3 verses](pres inf act) "Mourn" is pentheo, which means "to bewail," "to mourn," "to go into mourning," and "to lament."  - "Mourn" is a Greek word that means "to bewail," "to mourn," "to go mourning" and "to lament." It is the same word used for "mourn" in the Beatitudes (Matthew 5:4).