buckle down

verb

1. informal.
   intr, adverb to apply oneself with determination

   to buckle down to a job

Idioms and Phrases

Set to work, apply oneself with determination, as in All right, we'll buckle down now and study for exams . Originating about 1700 as buckle to , the expression gained currency with the football song “Buckle-Down, Winsocki” (from the Broadway musical comedy Best Foot Forward , 1941). [Mid-1800s]