Though angry about, backed, too, and cheered on (6)
I believe the answer is:
rooted
'cheered on' is the definition.
'rooted' can be an answer for 'cheered' (I've seen this in another clue). I am not sure about the 'on' bit.
'though angry about backed too' is the wordplay.
'though angry' becomes 'red' (someone may go red when angry. I am not sure about the 'though' bit.).
'about' indicates putting letters inside.
'backed' says the letters should be written backwards.
'too' written backwards gives 'oot'.
'red' going around 'oot' is 'ROOTED'.
'and' acts as a link.
Can you help me to learn more?
(Other definitions for rooted that I've seen before include "Fixed to the spot like a plant" , "Stuck to the spot" , "Firmly established in a plantlike way" , "Deeply felt" , "Firmly established and well planted" .)