From Longman Dictionary of Contemporary English rein something ↔ in (also rein something ↔ back British English) phrasal verb 1 to start to control a situation more strictly The government is reining in public expenditure. 2 to make a horse go more slowly by pulling on the reins → rein → See Verb table Examples from the Corpus rein in • Bandelier did prompt his parents to take steps to rein Kip in. • Impressions gleaned in...