Cloudy, close to covering most of large structure? (7)
I believe the answer is:
nebular
'cloudy' is the definition.
(similar in meaning)
'close to covering most of large structure?' is the wordplay.
I cannot quite see how this works, but
'large' could be 'l' (eg in clothes sizes) and 'l' is found in the answer.
'structure?' could be 'neb' (neb is a kind of structure) and 'neb' is present in the answer.
The remaining letters 'uar' 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 nebular that I've seen before include "Cloudy" , "Hazy and formless" , "Ran blue (anag)" , "Misty" , "Relating to astronomical cloud" .)