Strong's G160 — αἰφνίδιος (adjective)
aiphnidios (aif-nid'-ee-os) adj.
1. unexpected
2. (adverbially) suddenly
[from a compound of G1 (as a negative particle) and G5316 (meaning non-apparent)]
KJV: sudden, unawares 
Root(s): G1, G5316 
Compare: G1810, G1819 
Hebrew root: φαίνω
Occurrences: 2