not think much of

not think much of (someone or something)

To have very little esteem or regard for someone or something; to have a negative opinion of someone or something. I can't tell my parents didn't think much of Mary's new boyfriend. The boss hasn't thought much of your work so far, so you'd better start trying a bit harder!
See also: much, not, of, think
Farlex Dictionary of Idioms.

not think much of

Have little regard for, have a low opinion of, as in Bill doesn't think much of the carpentry work in that house. The phrase not much has been used in this sense since the mid-1800s.
See also: much, not, of, think
The American Heritage® Dictionary of Idioms by Christine Ammer.
See also:
  • be/have done with somebody/something
  • be in line with (someone or something)
  • better of
  • (someone or something) promises well
  • begin with
  • begin with (someone or something)
  • bird has flown, the
  • beware of
  • beware of (someone or something)
  • be rough on (someone or something)
References in periodicals archive
Comer does not think much of some of the approaches that are popular with many of the readers of this journal.
A method to his mastery: James Comer's enigmatic model for school success
However, my mother did not think much of the Western lifestyle in which she found our family.
The life of a Chinese American female physician executive