pale at (something)
To become fearful of, nervous about, or averse to something. Typically followed by "the thought/notion of (something)." I know that David pales at the thought of flying in an airplane. We paled at the notion of shutting down the company that our great-great-grandfather created.
pale at something
to become weak, frightened, or pale from fear of something or the thought of something. Bob paled at the thought of having to drive all the way back to get the forgotten suitcase. We paled at the notion that we would always be poor.