1) to fall beside or near something
2) a lapse or deviation from truth and uprightness
2a) a sin, misdeed
Part of Speech: noun neuter
Citing in TDNT: 6:170, 846
From G3895; a side slip (lapse or deviation), that is, (unintentional) error or (wilful) transgression: - fall, fault, offence, sin, trespass.
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 παράπτωμα; click on the second column to search for that grammatical form of the root παράπτωμα; click on the third column to search for that word and grammatical form; click on the total to search for the root παράπτωμα.