A past tense form of climb used in some dialects or archaic English, though 'climbed' is now standard.
From Old English climban. The form 'clum' appears to be a dialectal or obsolete strong past tense formation, before English standardized 'climbed' as the regular past tense.
Words like 'clum' show that English once had many irregular verbs—'sing, sang, sung' and 'climb, clum' worked the same way, but as English simplified over time, most verbs became regular, making 'clum' obsolete except in historical texts and dialects.
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