1) inconsiderably, without purpose, without just cause
2) in vain
2a) without success or effort
Part of Speech: adverb
Citing in TDNT: 2:380, 203
Probably from G1502 (through the idea of failure); idly, that is, without reason (or effect): - without a cause, (in) vain (-ly.)
|a without reason||89.20|
|b with no result||89.54|
|c for no purpose||89.63|
These two sites give similar information, with the definition from several dictionaries and statistics on the use of the word.
Perseus Digital Library
University of Chicago's Logion lexicon
Thayer's dictionary plus other information.
From this site's dictionary (in Italian)
Click on the first column to search for that word as a form of the root εἰκῇ; click on the second column to search for that grammatical form of the root εἰκῇ; click on the third column to search for that word and grammatical form; click on the total to search for the root εἰκῇ.