Tumbler at upper limit meets unacknowledged barrier to advancement (5,7)
I believe the answer is:
glass ceiling
'barrier to advancement' is the definition.
(I've seen this in another clue)
'tumbler at upper limit' is the wordplay.
'tumbler' becomes 'glass' (I've seen this in another clue).
'at' is a charade indicator (letters next to each other).
'upper limit' becomes 'ceiling' (I've seen this before).
'glass'+'ceiling'='GLASS CEILING'
'meets unacknowledged' acts as a link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for glass ceiling that I've seen before include "Unseen barrier to women's advancement" , "Unacknowledged barrier to career advancement" , "It prevents the promotion of minorities and women" , "Barrier affecting women and minorities" , "Artificial bar to promotion" .)