Stand a rough sea and a bit of a swell (5)
I believe the answer is:
easel
'stand' is the definition.
(stand for an artist's canvas)
'a rough sea and a bit of a swell' is the wordplay.
'a rough' indicates an anagram (a rough or broken ordering of the letters).
'and' is a charade indicator (letters next to each other).
'a bit of a swell' becomes 'el' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'sea' with letters rearranged gives 'eas'.
'eas'+'el'='EASEL'
Can you help me to learn more?
(Other definitions for easel that I've seen before include "Painter's tripod" , "Artist's canvas suppot" , "Lease it out to the artist" , "Painting support" , "Blackboard-frame" .)