A person who calumniates (slanders, or makes personal attacks upon, others).
Someone or something with similar claims of quality or distinction as another.
A competitor (person, team, company, etc.) with the same goal as another, or striving to attain the same thing. Defeating a rival may be a primary or necessary goal of a competitor.
To be equal to, or match, or to surpass another.
To oppose or compete with.
To strive to equal or excel; to emulate.
Having the same pretensions or claims; standing in competition for superiority.