Noble lady is seen in tent mostly (8)
I believe the answer is:
marquise
'noble lady' is the definition.
(marquise is a type of female aristocrat)
'is seen in tent mostly' is the wordplay.
'seen in' indicates putting letters inside.
'tent' becomes 'marquee' (marquee is a kind of tent).
'mostly' means to remove the last letter.
'marquee' with its last letter taken away is 'marque'.
'is' going into 'marque' is 'MARQUISE'.
(Other definitions for marquise that I've seen before include "Noble" , "Noblewoman" , "Sweet" .)