1
general::
Furious, enraged, as in I've been waiting for two hours and am fit to be tied. This expression implies anger so extreme that it requires physical restraint. [Late 1800s]
American Heritage Idioms
2
general::
Phrase(s): fit to be tied
angry and agitated. (As if needing to be restrained.) • Joe was fit to be tied when his wife told him she was leaving. • I was fit to be tied when Mary tried to be friendly, after three years of not speaking to me.
McGrawhill's American Idioms And Phrasal Verbs