(n): a person who pleads for a cause or propounds an idea
(n): an ardent and enthusiastic supporter of some person or activity
(n): a person who backs a politician or a team etc.
(n): a pike with a long tapering double-edged blade with lateral projections; 16th and 17th centuries
(n): medieval weapon consisting of a spearhead attached to a long pole or pikestaff; superseded by the bayonet