1) to announce that one is about to do or furnish something
1a) to promise (of one's own accord) to engage voluntarily
2) to profess
2a) an art, to profess one's skill in something
Part of Speech: verb
Citing in TDNT: 2:576, 240
From G1909 and the base of G32; to announce upon (reflexively), that is, (by implication) to engage to do something, to assert something respecting oneself: - profess, (make) promise.
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 ἐπαγγέλλομαι; click on the second column to search for that grammatical form of the root ἐπαγγέλλομαι; click on the third column to search for that word and grammatical form; click on the total to search for the root ἐπαγγέλλομαι.