It makes one unfit for high position! (7)
I believe the answer is:
vertigo
This clue could be a double definition.
'it makes one unfit' is the first definition.
The definition suggests a singular noun which matches the answer.
'high position' is the second definition.
The answer and definition can be both states of affairs as well as being singular nouns.
Maybe there's a link between them I don't understand?
'for' acts as a link.
Can you help me to learn more?
(Other definitions for vertigo that I've seen before include "Lightheadedness, dizziness" , "Forty Thieves' password" , "unbalanced feeling" , "Disturbance in the inner ear" , "Hitchcock film - giddiness" .)