leanness, scarcity, exiguity, scantness, meagerness, meagreness, underage, defect, poorness, excess, impoverishment, spareness, thinness.
insufficiency (part of speech: noun)
incompleteness (part of speech: noun)
littleness (part of speech: noun)
noncompletion (part of speech: noun)
smallness (part of speech: noun)