Having left at four I had got angry (5)
I believe the answer is:
livid
'angry' is the definition.
(I've seen this in another clue)
'having left at four i had' is the wordplay.
'having left' becomes 'l' (I've seen this in other clues).
'at' means one lot of letters go next to another.
'four' becomes 'IV' (Roman numerals).
'i had' becomes 'I'd' (common contraction).
'l'+'iv'+'id'='LIVID'
'got' acts as a link.
(Other definitions for livid that I've seen before include "Discoloured by bruising" , "Angry; marked with bruise" , "Unpleasantly colourful" , "Apoplectic" , "in a paddy" .)