Tiger perhaps a bit upset about getting caught, initially (3,3)
I believe the answer is:
big cat
'tiger perhaps' is the definition.
(tiger is a kind of big cat)
'a bit upset about getting caught initially' is the wordplay.
'upset' indicates anagramming the letters.
'about' means one lot of letters goes inside another.
'initially' suggests taking the first letters.
The initial letters of 'getting caught' is 'gc'.
'a'+'bit'='abit'
'abit' with letters rearranged gives 'biat'.
'biat' placed around 'gc' is 'BIG CAT'.
(Other definitions for big cat that I've seen before include "'Tiger or lion (3,3)'" , "ounce, say" , "Lion or tiger, say" , "Lion, for example" , "One may have pride" .)