(I) hope not

(I) hope not

1. I wish or desire that something is not or will not be the case. A: "I don't think we'll have to work this weekend." B: "Hope not! I've got big plans!" There's a chance that the engine is busted, but I hope not.
2. I would naturally expect that this would not happen or be true. A: "Don't worry, you won't have to pay for the additional service." B: "I certainly hope not, seeing as I never agreed to it in the first place!"
See also: hope, not
Farlex Dictionary of Idioms.

(I) hope not.

a phrase expressing the desire and wish that something is not so. John: It looks like it's going to rain. Jane: Hope not. John: The Wilsons said they might come over this evening. Jane: I hope not. I've got things to do.
See also: hope, not
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • hope not
  • not for a second
  • aint
  • ain't
  • not for a minute
  • not for a moment
  • iota
  • not an iota
  • not for a instant
  • not for a/one minute/moment/second/instant