to make you feel shocked and angry, especially because you strongly disapprove of something [= disgust]:
The thought of such cruelty sickened her.
All decent people should be sickened by such a pointless waste of life.
2 [intransitive] old-fashioned
to gradually become very ill:
The older people just sickened and died as food supplies ran low.
be sickening for somethingphrasal verb
Perhaps you're sickening for something.
sicken of somethingphrasal verb
He finally sickened of the endless round of parties and idle conversation.