tar(noun, verb) noun1. any of various dark heavy viscid substances obtained as a residueSimilar word(s): pitchDefinition categories: substance, bitumen2. a man who serves as a sailorSimilar word(s): gob, jack, mariner, seafarer, seamanDefinition categories: person, crewman, sailor verb1. coat with tar- tar the roof- tar the roadsDefinition categories: contact, coat, surfaceSentences with tar as a verb:- Although he was found innocent, the allegations had tarred his name.