As politicians, like fish out of water (3)
I believe the answer is:
wet
'water' is the definition.
(thesaurus)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for wet that I've seen before include "Watery" , "Moist or Soaked" , "Moisture; feeble (colloq.)" , "Saturated; rainy" , "Rainy (weather)" .)