Force pear initially into lime mixture (5)
I believe the answer is:
impel
'force' is the definition.
(I know that force can be written as impel)
'pear initially into lime mixture' is the wordplay.
'initially' suggests taking the first letters.
'into' means one lot of letters goes inside another.
'mixture' is an anagram indicator.
The first letter of 'pear' is 'p'.
'lime' with letters rearranged gives 'imel'.
'p' going within 'imel' is 'IMPEL'.
(Other definitions for impel that I've seen before include "Drive or coerce" , "'Drive, force (5)'" , "Urge forward - push" , "Egg" , "Make" .)