Regardless of what's in a vacuum? (2,6)
I believe the answer is:
no matter
This clue might be a double definition.
'regardless of' is the first definition.
(I've seen this before)
'a vacuum?' is the second definition.
(I've seen this before)
'what's in' is the link.
I am not very happy about this link. Some or all of it may belong to one of the definitions.
Can you help me to learn more?
(Other definitions for no matter that I've seen before include "It's not important - what a torment" , "Who cares" , "It's of little consequence - what a torment" , "Don't mind" , "Never mind" .)