Show a consuming interest in things (3)
I believe the answer is:
eat
'interest in things' is the definition.
The answer and definition can be both to do with human feelings as well as being verbs in their base form.
Maybe there's a link between them I don't understand?
'show a consuming' is the wordplay.
'show' becomes 'et' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'consuming' indicates putting letters inside.
'et' placed around 'a' is 'EAT'.
Can you help me to learn more?
(Other definitions for eat that I've seen before include "Corrode" , "Feed" , "Gobble up" , "get stuck in" , "Consume (food)" .)