River otters hoarding rubbish (3)
I believe the answer is:
rot
'rubbish' is the definition.
(both can mean nonsense)
'river otters hoarding' is the wordplay.
'hoarding' indicates a hidden word.
'ROT' is hidden within 'river otters'.
(Other definitions for rot that I've seen before include "Codswallop" , "Decay in grotesque way" , "Decay, moulder" , "Gradual decline" , "Decay, wither" .)