imperfection
Word family (noun) perfection ≠ imperfection perfectionist perfectionism perfectibility (adjective) perfect ≠ imperfect perfectible perfectionist (verb) perfect (adverb) perfectly ≠ imperfectly
From Longman Business Dictionaryimperfectionim‧per‧fec‧tion /ˌɪmpəˈfekʃən-pər-/ noun [countable] something that is not completely correct or perfect in a system, product etcSYNFLAWThe CD had several small imperfections.