Captivate 1,440, but with the first off (7)
I believe the answer is:
engross
'captivate' is the definition.
(thesaurus)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for engross that I've seen before include "Completely absorb" , "Totally absorb the attention of" , "Occupy attention fully, absorb" , "grab attention" , "Absorb the attention of (someone)" .)