Rejects five, the last on one foot (6)
I believe the answer is:
vetoes
'rejects' is the definition.
The definition and answer can be both to do with communicating as well as being verbs in their -s form.
Perhaps they are linked in a way I don't understand?
'five the last on one foot' is the wordplay.
'five' becomes 'V' (Roman numeral).
'last' indicates one should take the final letters.
'on one foot' becomes 'toes' (I can't justify this - if you can you should give a lot more credence to this answer).
The final letter of 'the' is 'e'.
'v'+'e'+'toes'='VETOES'
Can you help me to learn more?
(Other definitions for vetoes that I've seen before include "Refuses to allow" , "Casts over-riding negative vote" , "Votes to block a decision" , "E votes to block decisions" .)