Element of basic education delivered in spare study (5)
I believe the answer is:
learn
'study' is the definition.
(I know that study can be written as learn)
'element of basic education delivered in spare' is the wordplay.
'element of basic education' becomes 'R' (as in the three R's).
'delivered in' means one lot of letters goes inside another.
'spare' becomes 'lean' (similar in meaning).
'r' inserted into 'lean' is 'LEARN'.
(Other definitions for learn that I've seen before include "Master" , "be taught a lesson" , "teach illiterate" , "Acquire 28 across" , "Study (at school?)" .)