WordNet records no synonym and no antonym for stencil. It is the only member of each of its synsets, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
a sheet of material (metal, plastic, cardboard, waxed paper, silk, etc.) that has been perforated with a pattern (printing or a design); ink or paint can pass through the perforations to create the printed pattern on the surface below
mark or print with a stencil
Synonyms, antonyms and the broader and narrower relations for stencil come from Princeton University’s WordNet. Full sources and licences.