1) deficiency, that which is lacking
2) in reference to property and resources, poverty, want, destitution
Part of Speech: noun neuter
Citing in TDNT: 8:592, 1240
From G5302; a deficit; specifically poverty: - that which is behind, (that which was) lack (-ing), penury, want.
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 ὑστέρημα; click on the second column to search for that grammatical form of the root ὑστέρημα; click on the third column to search for that word and grammatical form; click on the total to search for the root ὑστέρημα.