Royal family study form, disregarding all outsiders (5)

I believe the answer is:
tudor
'royal family' is the definition.
(Tudor is an example)
'study form disregarding all outsiders' is the wordplay.
I cannot quite see how this works, but
'study' could be 'do' (to 'do' a subject at university is to study it) and 'do' is present in the answer.
The remaining letters 'tur' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for tudor that I've seen before include "Royal family, fourteen eighty five to sixteen hundred and three" , "Welsh royal family" , "Name of English royal family during 16th century" , "Elizabeth I of England was of this royal family" , "Rose" .)
