European garlic's beginning to pong! (5)
I believe the answer is:
greek
'european' is the definition.
(Greek is an example)
'garlic's beginning to pong' is the wordplay.
'beginning to' indicates taking the first letters.
'pong' becomes 'reek' (I've seen this before).
The first letter of 'garlics' is 'g'.
'g'+'reek'='GREEK'
(Other definitions for greek that I've seen before include "(All) incomprehensible (to me)" , "Classical language" , "Athenian?" , "National?" , "Hellene" .)