From Longman Dictionary of Contemporary Englishput the boot input the boot inBritish English informal a) UNKINDto criticize or be cruel to someone who is already in a bad situation b) ATTACKto attack someone by kicking them repeatedly, especially when they are on the ground → boot
Examples from the Corpus
put the boot in• At her wedding Phil took spectacularly to the bottle and put the boot in with some brio.• And putting the boot in ... the recycling service for wellies.• Gregory put the boot in ... metaphorically speaking!• Time had put the boot in.• I think they just sucked up to David, and began to put the boot in really, quite unnecessarily and unfairly.• And the judge, emboldened by the new case management powers decides to put the boot in.• Low-brow pedestrians of all parties, egged on by the press, were only too happy to put the boot in.• I wouldn't like to be stuck down a dark alley at night with whoever put the boot in here. 