Label attached to a southern county: 'It's saucy!' (7)
I believe the answer is:
tabasco
'it's saucy' is the definition.
(tabasco is a sauce)
'label attached to a southern county' is the wordplay.
'label' becomes 'tab' (I've seen this in another clue).
'attached to' means one lot of letters go next to another.
'southern' becomes 's' (abbreviation).
'county' becomes 'co'.
'tab'+'a'+'s'+'co'='TABASCO'
(Other definitions for tabasco that I've seen before include "Mexican state; pungent sauce" , "A hot spicy sauce" , "Hot peppery sauce" , "condiment?" , "Spicy pepper sauce" .)