Angry girl hiding in cover (5)
I believe the answer is:
livid
'angry' is the definition.
(I've seen this in another clue)
'girl hiding in cover' is the wordplay.
'girl' becomes 'Liv'.
'hiding in cover' becomes 'id' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'liv'+'id'='LIVID'
Can you help me to learn more?
(Other definitions for livid that I've seen before include "some more [old cardinals]" , "Furiously angry - leaden coloured?" , "Apoplectic" , "Furiously angry, the colour of lead" , "Enraged" .)