Victim tense in Mary Rose at the front (6)
I believe the answer is:
martyr
'victim' is the definition.
(I know that martyr is a type of victim)
'tense in mary rose at the front' is the wordplay.
'tense' becomes 't' (grammatical abbreviation).
'in' means one lot of letters goes inside another.
'at the front' indicates taking the first letters.
The first letter of 'rose' is 'r'.
't' placed inside 'mary' is 'marty'.
'marty'+'r'='MARTYR'
(Other definitions for martyr that I've seen before include "One who dies for a cause" , "Victim; eg St Stephen" , "Person dying for their faith" , "One who suffers death rather than renounce their religion" , "One suffering or dying for a cause" .)