Express anger and increase it to fifty (5)
I believe the answer is:
growl
'it to fifty' is the definition.
The definition suggests a singular noun which matches the answer.
'express anger and increase' is the wordplay.
'express anger' becomes 'l' (I am not sure about this - if you are sure you should believe this answer much more).
'and' is a charade indicator (letters next to each other).
'increase' becomes 'grow' (growing is a kind of increasing).
'l' after 'grow' is 'GROWL'.
Can you help me to learn more?
(Other definitions for growl that I've seen before include "Show aggression as boxer" , "Grumble; roar" , "warn of attack" , "Hostile dog's noise" , "Hostile animal's sound" .)