Lowest point from within a dirigible (5)
I believe the answer is:
nadir
'lowest point' is the definition.
(I've seen this before)
'from within a dirigible' is the wordplay.
'from' indicates a hidden word.
'NADIR' can be found hidden inside 'within a dirigible'.
(Other definitions for nadir that I've seen before include "Floor of drain in need of repair" , "Low spot" , "Given lowest place" , "Point opposite the zenith" , "Drain (anag)" .)