Seem rotund perhaps, and large (10)
I believe the answer is:
tremendous
'large' is the definition.
('tremendous' can be similar in meaning to 'large')
'seem rotund perhaps' is the wordplay.
'perhaps' indicates anagramming the letters.
'seem'+'rotund'='seemrotund'
'seemrotund' with letters rearranged gives 'TREMENDOUS'.
'and' acts as a link.
(Other definitions for tremendous that I've seen before include "Wonderful" , "Immense" , "Fantastic" , "large" , "Terrific" .)