Nudged four leading engineers towards sudden drop (8)
I believe the answer is:
nosedive
'sudden drop' is the definition.
(I've seen this before)
'nudged four leading engineers' is the wordplay.
'nudged' becomes 'nosed' (I am not sure about this - if you are sure you should believe this answer much more).
'four' becomes 'IV' (Roman numerals).
'leading' indicates taking the first letters (the leading letter of the word).
The first letter of 'engineers' is 'e'.
'nosed'+'iv'+'e'='NOSEDIVE'
'towards' acts as a link.
This may not be right. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for nosedive that I've seen before include "fall precipitately" , "sudden drop" , "headlong plunge" , "Take the plunge suddenly" , "steep fall" .)