Frenchman giving engineers directions (4)
I believe the answer is:
rene
'frenchman' is the definition.
(common French name)
'giving engineers directions' is the wordplay.
'giving' is a charade indicator (letters next to each other).
'engineers' becomes 're' (abbreviation for Royal Engineers).
'directions' becomes 'ne' (I've seen this in other clues).
're' next to 'ne' is 'RENE'.
(Other definitions for rene that I've seen before include "- Lalique, glass artist" , "- Descartes, French mathematician" , "-- Magritte, artist" .)