Prove wrong to get out of bed? (6)
I believe the answer is:
debunk
This clue is a double definition.
'prove wrong' is the first definition.
(to debunk something is to prove it's wrong)
'get out of bed?' is the second definition.
(de-bunk could mean to get out of a bunk)
'to' is the link.
(Other definitions for debunk that I've seen before include "Expose false claim" , "Show to be falsely honoured" , "Reveal as false, show up" , "Disprove" , "Show to be false or unjustified" .)