no-no 
noun (plural no-nos) informal
A thing that is not possible or acceptable: perming highlighted hair used to be a definite no-no, but it’s now possible...
- So an office at that end of the building is a definite no-no as the droning hum could drive me mad.
- That sort of event was a definite no-no and he worked hard to prevent such things.
- Wiggling out was a definite no-no since he had already made sure that I had nowhere else to turn to.
Rhymes
- perfecting cylinder
- perfecting machine
- perfecting press
- perfection
- perfectional
- perfectionate
- perfectionated
- perfectionation
- perfectioned
- perfectioner
- perfectioning
- perfectionism
- perfectionist
- perfectionistic
- perfectionize
- perfectionment
- Perfectist
- perfectivation
- share and share alike
- share capital
- sharecrop
- sharecropper
- shared care
- sharedness
- shared ownership