Sea of whiskey? (5)
I believe the answer is:
irish
This clue is a double definition.
'sea' is the first definition.
(Irish Sea)
'whiskey?' is the second definition.
(I know that Irish is a type of whiskey)
'of' is the link.
(Other definitions for irish that I've seen before include "One setter" , "Reddish-brown dog" , "Kind of whiskey" , "Sort of coffee, stew or terrier" , "Of this place" .)