Refers to saliva that drips from the mouth, often involuntarily (e.g., while sleeping, or when hungry).
The baby is drooling.
おいしそうな匂いに、思わずよだれが出た。
The delicious smell made my mouth water involuntarily.
The dog drooled at the sight of the feast.
Babies often drool while sleeping.
The mother wiped her child's drool with a towel.
The delicious-looking dish made my mouth water.