keep a tight rein on(redirected from keep a close rein on)
keep a tight rein on (someone or something)
To maintain strict or tight control over someone; to not allow someone 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.
keep a tight rein on someone or somethingand 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.