Boanerges = "sons of thunder"
1) a nickname given to James and John, the sons of Zebedee, by the Lord. The name seems to denote fiery and destructive zeal that may be likened to a thunder storm.
Part of Speech: noun proper masculine
Of Chald origin ([H1123] and [H7266]); sons of commotion; Boanerges, an epithet of two of the Apostles: - Boanerges.
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 Βοανηργές; click on the second column to search for that grammatical form of the root Βοανηργές; click on the third column to search for that word and grammatical form; click on the total to search for the root Βοανηργές.