Rubbish tango: move like a duck! (7)
I believe the answer is:
twaddle
'rubbish' is the definition.
(I've seen this before)
'tango move like a duck' is the wordplay.
'tango' becomes 'T' (phonetic alphabet: alpha, bravo, charlie etc.).
'move like a duck' becomes 'waddle' (I've seen this before).
't'+'waddle'='TWADDLE'
(Other definitions for twaddle that I've seen before include "Pretentious or silly talk" , "Trivial/foolish speech" , "Trivial speech/writing" , "Foolish words" , "tripe" .)