Refuge mostly small and ugly (7)
I believe the answer is:
hideous
'ugly' is the definition.
(similar in meaning)
'refuge mostly small and' is the wordplay.
'refuge' becomes 'hide-out' (I've seen this before).
'mostly' means to remove the last letter.
'small and' becomes 's' (I am not sure about this - if you are sure you should believe this answer much more).
'hideout' with its last letter removed is 'hideou'.
'hideou'+'s'='HIDEOUS'
Can you help me to learn more?
(Other definitions for hideous that I've seen before include "Unsightly" , "Extremely ugly" , "Horrible" , "Ghastly" , "revolting" .)