Son and I seem upset about a cat (7)
I believe the answer is:
siamese
'cat' is the definition.
(Siamese is an example)
'son and i seem upset about a' is the wordplay.
'son' becomes 's' (**).
'and' means one lot of letters go next to another.
'upset' is an anagram indicator.
'about' means one lot of letters goes inside another.
'seem' with letters rearranged gives 'mese'.
'mese' going around 'a' is 'amese'.
's'+'i'+'amese'='SIAMESE'
(Other definitions for siamese that I've seen before include "type of cat" , "like a cat" , "Cat - Thai?" , "cats?" , "Thease twins are joined at birth" .)