Thus accepting an outcome of sunbathing is very bad (7)
I believe the answer is:
satanic
'bad' is the definition.
(I've seen this before)
'thus accepting an outcome of' is the wordplay.
'thus' becomes 'sic' ('thus' in Latin).
'accepting' indicates putting letters inside (inserted letters are accepted).
'an outcome of' becomes 'atan' (I can't justify this - if you can you should give a lot more credence to this answer).
'sic' placed around 'atan' is 'SATANIC'.
'sunbathing is very' 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 satanic that I've seen before include "Very evil and cruel" , "Fiendish" , "Diabolic" , "Devilish (as Blake's 18)" , "Devil-like" .)