1) unfermented, free from leaven or yeast
1a) of the unleavened loaves used in the paschal feast of the Jews
1b) metaphorically free from faults or the "leaven of iniquity"
Part of Speech: adjective
Citing in TDNT: 2:902, 302
From G1 (as a negative particle) and G2219; unleavened, that is, (figuratively) uncorrupted; (in the neuter plural) specifically (by implication) the Passover week: - unleavened (bread).
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 ἄζυμος; click on the second column to search for that grammatical form of the root ἄζυμος; click on the third column to search for that word and grammatical form; click on the total to search for the root ἄζυμος.