1
general::
Feeling nervous or terrified, as in When I looked over the cliff, I broke out in a cold sweat. This expression refers to perspiring accompanied by a feeling of cold, which can be induced by acute fear as well as by fever. [Late 1700s]
American Heritage Idioms
2
general::
Phrase(s): in a cold sweat
in a state of fear. • He stood there in a cold sweat, waiting for something bad to happen. • I was in a cold sweat while they counted the ballots.
McGrawhill's American Idioms And Phrasal Verbs