Respectful at all times during split (8)
I believe the answer is:
reverent
'respectful' is the definition.
(similar in meaning)
'at all times during split' is the wordplay.
'at all times' becomes 'ever' (synonyms).
'during' indicates putting letters inside.
'split' becomes 'rent' (past tense of 'rend' meaning to split).
'ever' going inside 'rent' is 'REVERENT'.
(Other definitions for reverent that I've seen before include "Deeply respectful" , "Showing great respect" , "showing much respect" , "Showing devout awe" , "worshipping" .)