lower

lower the boom on

1 treat someone severely.

2 put a stop to an activity.

☞ It has been suggested that this phrase originally meant 'knocking out an adversary with one punch' in a fight.

lower the tone diminish the spirit or moral character of a conversation, place, etc.

☞ Tone here is used to mean the general character or attitude of a conversation, place, piece of writing, etc.

lower your guard: seeguard.

lower your sights: see raise your sightsatsight.