What is another word for underestimated?

Here are some words that can be used as synonyms for "underestimated":

Formal:

* Disparaged

* Undervalued

* Minimized

* Downplayed

* Disregarded

Informal:

* Underappreciated

* Overlooked

* Taken for granted

* Slipped through the cracks

* Missed the boat on

* Didn't give enough credit to

The best word choice will depend on the specific context of your sentence.