Solid work at University perhaps involves Republican (6)
I believe the answer is:
sturdy
'solid' is the definition.
(synonyms)
'work at university perhaps involves republican' is the wordplay.
'work at university perhaps' becomes 'study'.
'involves' means one lot of letters goes inside another.
'republican' becomes 'r' (abbreviation).
'study' enclosing 'r' is 'STURDY'.
(Other definitions for sturdy that I've seen before include "Strong and stout" , "Uncompromising" , "Powerful" , "Well-built - strapping" , "Strong, solid" .)