Strong’s Greek
G5513 — chliaros
The entry below is Strong’s own definition (1890, public domain), and every verse where the word occurs.
χλιαρός
chliaros — pronounced khlee-ar-os'
from chlio (to warm); tepid:--lukewarm.
1 occurrence in the KJV.
Revelation 3:16
So then because thou art lukewarm, and neither cold nor hot, I will spue thee out of my mouth.