Howl grievously, worried after opera is given up (7)
I believe the answer is:
ululate
'howl' is the definition.
(I know that howl can be written as ululate)
'grievously worried after opera is given up' is the wordplay.
'grievously worried' becomes 'ate' (something worrying may eat someone up. I am not sure about the 'grievously' bit.).
'after' says to put letters next to each other.
'opera' becomes 'lulu' (opera by Alban Berg).
'is given up' says the letters should be written in reverse (in a down clue, letters go up).
'lulu' reversed gives 'ulul'.
'ate' put after 'ulul' is 'ULULATE'.
Can you help me to learn more?
(Other definitions for ululate that I've seen before include "Emit long loud cries" , "Howl loudly" , "Howl, wail, screech" , "Wail or lament loudly" , "Express grief" .)