Without notice, serviceman's in a pickle (8)
I believe the answer is:
marinade
'a pickle' is the definition.
(I've seen this before)
'without notice serviceman's' is the wordplay.
'without' is an insertion indicator.
'notice' becomes 'ad'.
'serviceman' becomes 'marine' (marine is a kind of serviceman**).
'ad' inserted inside 'marine' is 'MARINADE'.
'in' acts as a link.
(Other definitions for marinade that I've seen before include "pickle" , "Type of star system" , "Spiced liquid in which food is soaked before cooking" , "Steep in seasoning" , "Mixtures used for soaking foods before cooking" .)