Barge in at midnight, eat rubbish and fall in a heap (4-5)
I believe the answer is:
gate-crash
'barge in' is the definition.
(synonyms)
'midnight eat rubbish and fall in a heap' is the wordplay.
I cannot really understand how this works, but
'midnight' could be 'g' (the middle letter in 'night') and 'g' is present in the answer.
an anagram of 'eat' is 'ate' which is present in the answer.
'fall' could be 'crash' (crashing is a kind of falling) and 'crash' is present in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'at' is the link.
Can you help me to learn more?
(Other definitions for gate-crash that I've seen before include "Enter (a party) without an invitation" , "Attend private party without invitation" , "Arrive uninvited" , "Intrude on private party without invitation" , "Go to party without being invited" .)