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English definition of “in-”

in-

prefix uk (before l il-, before b, m or p im-, before r ir-)   /ɪn-/ us  
used to add the meaning 'not', 'lacking', or 'the opposite of' to adjectives and to words formed from adjectives: incomplete/incompletely illegal/illegally impossible/impossibly irregular/irregularly
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Yes, no and not
(Definition of in- prefix from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)
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