WordNet sense 1 (a wad of something chewable as tobacco):

chew, cud, quid, wad, chaw

WordNet sense 2 (blatant or sensational promotion):

ballyhoo, hoopla, hype

WordNet sense 3 (electrical device that fits into the cylinder head of an internal-combustion engine and ignites the gas by means of an electric spark):

spark plug, sparking plug

WordNet sense 4 (an electrical device with two or three pins that is inserted in a socket to make an electrical connection):

male plug

WordNet sense 5 (blockage consisting of an object designed to fill a hole tightly):

stopper, stopple

WordNet sense 6 (an upright hydrant for drawing water to use in fighting a fire):

fireplug, fire hydrant

WordNet sense 7 (an old or over-worked horse):

hack, jade, nag

WordNet sense 8 (fill or close tightly with or as if with a plug):

secure, stop up

WordNet sense 9 (deliver a quick blow to):

punch

WordNet sense 10 (persist in working hard):

plug away