Synonyms for Mouthy:

adj.

•insolent (adjective)
callous, sacrilegious, audacious, irreverent, brazen, impolite, saucy, flagrant, candid, presumptuous, arrogant, impertinent, discourteous, brash, rude, sarcastic, disrespectful, derisive, contemptuous, insolent, outrageous, insubordinate, defiant, bold, outspoken, cheeky.
•rhetorical (adjective)
oratorical, pompous.
•sassy (adjective)
discourteous, rude, disrespectful, brazen, insolent, bold, audacious.

n.

impudent, ill-mannered, offensive, smart, abrasive. •bombastic (noun)
pompous, loud-mouthed, oratorical.

Other synonyms:

•Other relevant words:
pompous, impudent, oratorical.