IPA: /ˌʌndərˈkʊkt/
KK: /ʌndərˈkʊkt/
Not cooked enough; still raw or not fully prepared.
The chicken was undercooked, so we had to put it back in the oven.
Undercooked is formed from "under-" (meaning beneath or insufficiently) and "cooked" (from Old English "cocian", meaning to prepare food by heating). The word describes food that has not been cooked enough, remaining insufficiently prepared.
Think of food that is 'beneath' the proper cooking level — 'under-' means insufficient, and 'cooked' refers to the preparation of food.