1) an adulteress
2) as the intimate alliance of God with the people of Israel was likened to a marriage, those who relapse into idolatry are said to commit adultery or play the harlot
2a) fig. equiv. to faithless to God, unclean, apostate
Part of Speech: noun feminine
Citing in TDNT: 4:729, 605
A prolonged form of the feminine of G3432; an adulteress (literally or figuratively): - adulteress (-ous, -y).
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 μοιχαλίς; click on the second column to search for that grammatical form of the root μοιχαλίς; click on the third column to search for that word and grammatical form; click on the total to search for the root μοιχαλίς.