[Adjective] A description of someone or something that is very good at getting you to agree to something. Example: John was so persuasive that Angela did his homework for him.
Found on http://www.bbc.co.uk/skillswise/glossary/
Per·sua'sive adjective [ Confer French persuasif .] Tending to persuade; having the power of persuading; as, persuasive eloquence. ' Persuasive words.' Milton. Found on http://www.encyclo.co.uk/webster/P/62