Feeling no end upset and catty (6)
I believe the answer is:
feline
'catty' is the definition.
(I've seen this in another clue)
'feeling no end upset' is the wordplay.
'no end' means to remove the last letter.
'upset' indicates an anagram.
'feeling' with its final letter taken off is 'feelin'.
'feelin' with letters rearranged gives 'FELINE'.
'and' is the link.
(Other definitions for feline that I've seen before include "(Relating to a) cat" , "Like a cat" , "Of or like cats" , "suitable for Skimbleshanks?" , "Scots dish" .)