Really without a key part, we gather (5)
I believe the answer is:
rally
'gather' is the definition.
(I know that rally is a more specific form of gather)
'really without a key' is the wordplay.
'without' suggests deleting specific letters.
'a key' becomes 'E' (a musical key).
'really' with 'e' taken away is 'RALLY'.
'part we' is the 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 rally that I've seen before include "Get better; car meet" , "Recover strength after illness" , "Get-together" , "exchange over the Net?" , "several shots" .)