verb
teethe
TEETH/tiːð/
To have baby teeth emerge through the gums.
The infant is teething, with two tiny lower teeth emerging through the gums.

Etymology
Middle English tethen already meant 'grow teeth.' It probably continues an unrecorded Old English verb based on 'tooth,' while the present meaning retains the literal sense of teeth emerging.
More examples
- Some babies teethe with very little discomfort.
- She teethed earlier than her older sister did.
- The baby is teething, and his gums look swollen.
Forms
teethe · teethes · teethed · teething