Teen idler fermented shandy (4-5)

I believe the answer is:

tree-lined

I'm a little stuck... Click here to teach me more about this clue!

'shandy' is the definition.
The answer and definition are not the same part of speech.

'teen idler fermented' is the wordplay.
'fermented' is an anagram indicator.
'teen'+'idler'='teenidler'
'teenidler' anagrammed gives 'TREE-LINED'.

Can you help me to learn more?

I've seen this clue in the Sydney Morning Herald.

Want a hint initially instead of a full solution? Install my app