Wet dress and muddy pants, first of all (4)
I believe the answer is:
damp
'wet' is the definition.
(I know that wet can be written as damp)
'dress and muddy pants first of all' is the wordplay.
'first of all' suggests taking the first letters.
The first letters of 'dress and muddy pants' is 'DAMP'.
(Other definitions for damp that I've seen before include "Somewhat moist" , "Rising -, TV sitcom" , "(Slightly) wet" , "soggy" , "Clammy" .)