A scientist may show his Nobel off, right? (5,4)
I believe the answer is:
niels bohr
'a scientist' is the definition.
(I've seen this before)
'his nobel off right?' is the wordplay.
'off' is an anagram indicator.
'right?' becomes 'r' (common abbreviation).
'his'+'nobel'='hisnobel'
'hisnobel' is an anagram of 'nielsboh'.
'nielsboh'+'r'='NIELS BOHR'
'may show' is the link.
(Other definitions for niels bohr that I've seen before include "Atomic scientist" , "14 [GREAT DANE]" , "Danish physicist" .)