IPA: /ˌʌndərˈdu/
KK: /ʌndərˈdu/
To do something in a way that is not enough or not sufficient, especially when cooking something for too little time.
If you underdo the chicken, it may not be safe to eat.
Past: underdid
Past Participle: underdone
Underdo → It is formed from "under-" (meaning below or insufficiently) and "do" (meaning to perform or execute). The word "underdo" means to perform something insufficiently or to do less than what is required.
Think of doing something 'below' ('under-') the expected level of performance — that's why underdo means to do less than what is needed.
No commonly confused words.