Explanation

His master often connives at his follies.

اس کا آقا اکثر اس کی حماقتوں پر اکتفا کرتا ہے۔

 "at". In the given sentence, it is given that the subject's master often ignores the subject's follies.

At is a preposition used after a verb (connives) to show that somebody tries to do something