Scientist is away in rubbishy spot (6)
I believe the answer is:
boffin
'scientist' is the definition.
(boffin is a kind of scientist)
'away in rubbishy spot' is the wordplay.
'away' becomes 'off' ('off' can be a synonym of 'away').
'in' means one lot of letters goes inside another.
'rubbishy spot' becomes 'bin' (I can't justify this - if you can you should believe this answer much more).
'off' put inside 'bin' is 'BOFFIN'.
'is' is the link.
Can you help me to learn more?
(Other definitions for boffin that I've seen before include "Back-room boy" , "Scientist (informal)" , "Scientist (in the back room?)" , "Brainbox" , "Research scientist" .)