Plug

an old or over-worked horse

blockage consisting of an object designed to fill a hole tightly

blatant or sensational promotion

an upright hydrant for drawing water to use in fighting a fire

an electrical device with two or three pins that is inserted in a socket to make an electrical connection

electrical device that fits into the cylinder head of an internal-combustion engine and ignites the gas by means of an electric spark

a wad of something chewable as tobacco

fill or close tightly with or as if with a plug

persist in working hard

insert a plug into

insert as a plug

replace the center of a coin with a baser metal

deliver a quick blow to

make a plug for; praise the qualities or in order to sell or promote