Strong's #1500: eike (pronounced i-kay')

probably from 1502 (through the idea of failure); idly, i.e. without reason (or effect):--without a cause, (in) vain(-ly).

Thayer's Greek Lexicon:

̓͂

eikē

1) inconsiderably, without purpose, without just cause

2) in vain

2a) without success or effort

Part of Speech: adverb

Relation: probably from G1502 (through the idea of failure)

Citing in TDNT: 2:380, 203

Usage:

This word is used 7 times:

 

Matthew 5:22: "is angry with his brother without a cause shall be in danger of the judgment:"
Romans 13:4: "not the sword in vain: for he is the minister of God,"
1 Corinthians 15:2: "unto you, unless ye have believed in vain."
Galatians 3:4: "Have ye suffered so many things in vain? if it be yet in vain."
Galatians 3:4: "in vain? if it be yet in vain."
Galatians 4:11: "of you, lest I have bestowed upon you labor in vain."
Colossians 2:18: "worshiping of angels, intruding into those things which he hath not seen, vainly puffed up"