Being ugly, keeps out of sight for half an hour (7)
I believe the answer is:
hideous
'being ugly' is the definition.
(similar in meaning)
'out of sight for half an hour' is the wordplay.
I cannot really understand how this works, but
'of' could be 'o' and 'o' is found in the answer.
'an' could be 'i' (Roman numeral for one) and 'i' is present in the answer.
'hour' could be 'h' (abbreviation) and 'h' is found in the answer.
The remaining letters 'deus' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'keeps' acts as a link.
Can you help me to learn more?
(Other definitions for hideous that I've seen before include "Horrible" , "Extremely unpleasant" , "Repulsive" , "Unsightly" , "revolting" .)