Perhaps Frank has a large temper (6)
I believe the answer is:
anneal
'temper' is the definition.
(I know that temper can be written as anneal)
'perhaps frank has a large' is the wordplay.
'perhaps frank' becomes 'anne' (Anne Frank, Holocaust victim. I am not sure about the 'perhaps' bit.).
'has' means one lot of letters go next to another.
'large' becomes 'L' (eg in clothes sizes).
'anne'+'a'+'l'='ANNEAL'
Can you help me to learn more?
(Other definitions for anneal that I've seen before include "Heat and cool slowly in order to toughen" , "Fire or glaze as in kiln" , "Long angry speech" , "Make tough" , "Temper by heat treatment" .)