IPA: /ˌʌndərˈsɛl/
KK: /ʌndərˈsɛl/
To sell something for a lower price than it is worth or lower than what others are selling it for.
The store decided to undersell its competitors to attract more customers.
Past: undersold
Past Participle: undersold
Undersell → It is formed from "under-" (meaning below or beneath) and "sell" (from Old English "sellan", meaning to give or to sell). The word "undersell" means to sell something at a lower price than another seller, thus placing it below in terms of price.
Think of selling something for a price that is 'below' ('under-') what others are asking — that's why undersell means to sell for less.