Strong's G772 — ἀσθενής (adjective)
asthenes (as-then-ace') adj.
1. strengthless, without strength
2. weak
{in various applications, literal, figurative and moral}
[from G1 (as a negative particle) and the base of G4599]
KJV: more feeble, impotent, sick, without strength, weak(-er, -ness, thing) 
Root(s): G1, G4599 
Hebrew root: σθενόω
Occurrences: 26