Port is used in making a toast (6)
I believe the answer is:
prosit
'toast' is the definition.
(I've seen this before)
'port is used' is the wordplay.
'used' indicates anagramming the letters.
'port'+'is'='portis'
'portis' is an anagram of 'PROSIT'.
'in making a' acts as a link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for prosit that I've seen before include "down the hatch" , "A German toast - good health" , "Good health!; tripos (anagram)" , "Bottoms up (in Germany)" , "Good health! Cheers!" .)