He is known as a caviller, always finding fault with everything.

The cavillers criticized every decision made by the committee.

She tends to cavil about every little detail.

She always finds something to cavil about, no matter how small or insignificant.

She constantly cavils about the smallest things.

The caviler always finds something to complain about.

The cavilers criticized every decision made by the committee.

She cavilled at every suggestion he made.

She is always cavilling about something.

Her constant cavilling about my work is starting to annoy me.