Fit to be tied (5)
'fit to be tied' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for irate that I've seen before include "Magical rod" , "Not happy" , "Ticked off" , "Narked" , "become irritated" .)
(Other definitions for apoplectic that I've seen before include "Seeing red" , "Overcome with anger" , "With red vision" , "Outraged" .)