Noun

1. Blockage consisting of an object designed to fill a hole tightly
2. A wad of something chewable as tobacco
3. Blatant or sensational promotion
4. Electrical device that fits into the cylinder head of an internal-combustion engine and ignites the gas by means of an electric spark
5. An electrical device with two or three pins that is inserted in a socket to make an electrical connection
6. An upright hydrant for drawing water to use in fighting a fire
7. An old or over-worked horse

Verb

1. Fill or close tightly with or as if with a plug
2. Persist in working hard
3. Deliver a quick blow to
4. Make a plug for; praise the qualities or in order to sell or promote
5. Insert a plug into
6. Insert as a plug