1) to abstain as a religious exercise from food and drink: either entirely, if the fast lasted but a single day, or from customary and choice nourishment, if it continued several days
Part of Speech: verb
Citing in TDNT: 4:924, 632
From G3523; to abstain from food (religiously): - fast.
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 νηστεύω; click on the second column to search for that grammatical form of the root νηστεύω; click on the third column to search for that word and grammatical form; click on the total to search for the root νηστεύω.