To oink is to make the grunting sound a pig makes. Pigs oink, an oink from the sty, oink oink.
It is the standard English rendering of the noise and it is taught to children alongside moo and baa. Every language renders it differently — the sound a pig actually makes has not changed, and the words for it vary wildly, which is a good demonstration that these words are conventions rather than recordings. Note that oink is recorded only from the twentieth century, which is surprisingly late.
1verboinkTo make the grunting sound a pig makes.
“The piglets oinked excitedly when the farmer brought their food.”
2nounsoundSuch a sound.
“The piglet gave a loud oink when the farmer picked it up.”
oink is an animal sound.
The word is purely imitative and is recorded only from the twentieth century, which is late for an animal noise. Earlier English rendered the sound differently.
Imitative of the sound.
Etymology from Wiktionary, CC BY-SA
Practised in A Song of Ice and Fire