This is the 3407th most frequent Swedish word.
begå
"Begå" means "to commit" (e.g., a crime or an act).
Here, 'begick' (past tense of 'begå') is used to describe the act of committing or performing something, specifically a mistake.
Han begick ett misstag på jobbet.
He made a mistake at work.
In this sentence, 'begår' is the present tense of 'begå', used to indicate executing or performing a criminal act.
Hon begår ett brott om hon gör det.
She commits a crime if she does that.
Here, 'begå' is used in its infinitive form, implying the potential action of making an error.