Engineers getting tax break (6)
I believe the answer is:
recess
'break' is the definition.
(synonyms)
'engineers getting tax' is the wordplay.
'engineers' becomes 're' (Royal Engineers).
'getting' says to put letters next to each other.
'tax' becomes 'cess' (I've seen this in other clues).
're'+'cess'='RECESS'
(Other definitions for recess that I've seen before include "Space set back in wall" , "Closed period for parliament" , "Short break" , "Small niche or court holiday" , "Niche; temporary cessation of parliament" .)