Help's about run dry (4)
I believe the answer is:
arid
'dry' is the definition.
('arid' can be similar in meaning to 'dry')
'help's about run' is the wordplay.
'help' becomes 'aid' ('aid' can be a synonym of 'help').
'about' means one lot of letters goes inside another.
'run' becomes 'r' (cricket abbreviation).
'aid' placed around 'r' is 'ARID'.
(Other definitions for arid that I've seen before include "Very dry; uninteresting" , "Dry and unfertile" , "Tedious; short of rain" , "Drought-hit" , "Dry and parched, as with regions" .)