A number bring pressure to bear, being resourceful (6)
I believe the answer is:
clever
'resourceful' is the definition.
(thesaurus)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for clever that I've seen before include "Quick and intelligent" , "Smart or quick at learning" , "& 18 Down Smart Alec" , "Bright; smart" , "expert" .)