Stimulate new learner I put in uniform (7)
I believe the answer is:
enliven
'stimulate' is the definition.
(I know that enliven is a more specific form of the action stimulate)
'new learner i put in uniform' is the wordplay.
'new' becomes 'n' (abbreviation as in New Testament NT).
'learner' becomes 'l' (as in a learner driver with L-plates on their car).
'put in' indicates putting letters inside (back).
'uniform' becomes 'even' (uniform can mean even or level).
'n'+'l'+'i'='nli'
'nli' placed inside 'even' is 'ENLIVEN'.
(Other definitions for enliven that I've seen before include "Inject vim into, energise" , "Bring excitement to" , "Put zip or vim into" , "Make more animated" , "Make more interesting" .)