Force engineers over supporting school planner (7)
I believe the answer is:
schemer
'planner' is the definition.
(I know that schemer is a type of planner)
'force engineers over supporting school' is the wordplay.
'force engineers over' becomes 'emer' (I can't justify this - if you can you should believe this answer much more).
'supporting' says to put letters next to each other (in a down clue, some letters go below others).
'school' becomes 'sch' (abbreviation).
'emer' after 'sch' is 'SCHEMER'.
Can you help me to learn more?
(Other definitions for schemer that I've seen before include "one inventing plots" , "Devious type" , "Person who plots" , "One making devious plans" , "Plotter, conspirator" .)