Submitted by György Chityil ... on Thu, 04/05/2018 - 20:32 Lemma: proofNgram Count: 1Starts with letter: YesIndefinite Article: aGoogle Ngram Count: 163690Sense count: 1Contained in other ngrams: 13Hierarchy: NounPresent ParticipleForms: proofedproofsForms Count: 2