Given up — I'm one to leave military body with honour in retirement (9)

I believe the answer is:

immolated

'given up' is the definition.
(immolate can mean sacrifice)

'i'm one to leave military body with honour in retirement' is the wordplay.
'one' becomes 'i' (Roman numeral).
'to leave' suggests deleting specific letters.
'military body' becomes 'detail' (detail can mean a small group of soldiers).
'with honour' becomes 'om' (Order of Merit. I am not sure about the 'with' bit.).
'in retirement' is a reversal indicator (retire can mean to go back or backwards).
'detail' with 'i' taken away is 'detal'.
'detal'+'om'='detalom'
'detalom' in reverse letter order is 'molated'.
'im'+'molated'='IMMOLATED'

I've seen this clue in The Guardian.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.