Strong's G3155 — μάτην (adverb)
maten (mat'-ayn) adv.
1. folly
2. (adverbially) to no purpose, futilely
[accusative case of a derivative of the base of G3145 (through the idea of tentative manipulation, i.e. unsuccessful search, or else of punishment)]
KJV: in vain 
Root(s): G3145 
See also: G3154 
Hebrew root: μασσάομαι
Occurrences: 2