Tom and Lilibet pander (5)
I believe the answer is:
cater
'pander' is the definition.
(I know this)
'tom and lilibet' is the wordplay.
'tom' becomes 'cat' (a tom is a male cat).
'and' says to put letters next to each other.
'lilibet' becomes 'er' (I can't justify this - if you can you should believe this answer much more).
'cat'+'er'='CATER'
Can you help me to learn more?
(Other definitions for cater that I've seen before include "Provide goods or services for" , "provide meals" , "Supply food for parties" , "React (anag.)" , "Provide what is needed or wanted" .)