See about a fellow entering the legislature (6)
I believe the answer is:
senate
'the legislature' is the definition.
(senate is a kind of legislature)
'see about a fellow entering' is the wordplay.
'about' says the letters should be written in reverse.
'a fellow' becomes 'tan' (I am not sure about this - if you are sure you should believe this answer much more).
'entering' means one lot of letters goes inside another.
'tan' in reverse letter order is 'nat'.
'see' going around 'nat' is 'SENATE'.
Can you help me to learn more?
(Other definitions for senate that I've seen before include "Second house of Government" , "The upper house in parliament or oireachtas" , "Governing body of ancient Rome" , "Legislative assembly" , "State assembly" .)