Strong's G2114 — εὐθυμέω (verb)
euthumeo (yoo-thoo-meh'-o) v.
1. to cheer up
2. (intransitively) be cheerful
3. (neuter comparative, adverbially) more cheerfully
[from G2115]
KJV: be of good cheer (merry) 
Root(s): G2115 
Hebrew root: εὔθυμος
Occurrences: 3