Past tense and past participle of abet; helped, encouraged, or supported someone in doing something wrong or illegal.
From abet (Old French abeter, from a- + beter, of Germanic origin) plus the regular past tense suffix -ed. The doubled 't' follows English spelling rules for short-vowel verbs.
In crime shows, detectives look for evidence that someone 'abetted' a crime—past tense makes it clear this help already happened and needs to be proven in court!
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