1. a person or tool that applies gum or adhesive
2. a young animal, especially a horse, that has lost its front teeth
Usage: informal; chiefly British
3. a toothless person
Usage: informal; dated

Examples

• The factory hired a gummer to seal the envelopes with adhesive.
• The old horse was a gummer, having lost most of its teeth years ago.
• He became a gummer after his dentures were lost in the accident.
• The gummer applied the sticky substance carefully to each edge.
• That gummer of a horse could barely chew its hay.