Lowest point for some in a dirigible (5)
I believe the answer is:
nadir
'lowest point' is the definition.
(I've seen this before)
'some in a dirigible' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'NADIR' is hidden within 'in a dirigible'.
'for' is the link.
(Other definitions for nadir that I've seen before include "least successful point" , "extremely low position" , "Drain into the lowest point (5)" , "Point of greatest despair" , "deep despair" .)