Confine engineers near stern (8)
I believe the answer is:
restrict
'confine' is the definition.
(restricting is a kind of confining)
'engineers near stern' is the wordplay.
'engineers' becomes 're' (Royal Engineers).
'near' says to put letters next to each other.
'stern' becomes 'strict' ('strict' can be a synonym of 'stern'**).
're'+'strict'='RESTRICT'
(Other definitions for restrict that I've seen before include "Subject to limitations" , "Put limits on" , "Keep under control" , "Place limits on" , "hamper" .)