General Dislike:
* Unpleasant
* Repulsive
* Offensive
* Objectionable
* Unsavory
* Unpalatable
* Revolting
* Disgusting
* Loathsome
* Abhorrent
Morally Repugnant:
* Immoral
* Unethical
* Inhumane
* Barbaric
* Wicked
* Vile
Unacceptable:
* Inappropriate
* Improper
* Unseemly
* Outrageous
* Unorthodox
* Shocking
* Outlandish
* Ridiculous
Other:
* Unwelcome
* Unwanted
* Repelling
The best synonym will depend on the context of your sentence.