keep a tight rein on somebody/something

keep a tight rein on (someone or something)

To maintain strict or tight control over someone or something; to not allow someone or something very much independence or autonomy. Ever since George nearly lost his life savings in a drunken poker match, his husband has started keeping a tight rein on him. The boss has kept a tight rein on her assistant since she hired her. We try to keep a tight rein on our expenditures, but that's not always possible.
See also: keep, on, rein, tight
Farlex Dictionary of Idioms.

keep a tight rein on someone or something

 and keep a close rein on someone or something
Fig. to watch and control someone or something diligently. (Alludes to controlling a horse by a tight grip on the reins.) The office manager kept a tight rein on the staff. Mary keeps a close rein on her children.
See also: keep, on, rein, tight
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

keep a tight rein on

exercise strict control over; allow little freedom to.
See also: keep, on, rein, tight
Farlex Partner Idioms Dictionary

keep a tight ˈrein on somebody/something

(also keep somebody/something on a tight ˈleash) control somebody/something very carefully; give somebody/something very little freedom: The company must keep a tight rein on spending. She keeps her children on a tight leash to make sure they don’t get into trouble. OPPOSITE: give/allow somebody/something free/full rein
A leash is used to hold and control a dog, and a rein is used to control a horse.
See also: keep, on, rein, somebody, something, tight
Farlex Partner Idioms Dictionary
See also:
  • better of
  • be/have done with somebody/something
  • be in line with (someone or something)
  • (someone or something) promises well
  • bird has flown, the
  • begin with
  • begin with (someone or something)
  • beware of
  • beware of (someone or something)
  • be rough on (someone or something)