What is the name of verbs that can not add ed suffix?

Verbs that cannot add the "-ed" suffix to form their past tense are called irregular verbs.

Here's why:

* Regular verbs follow a predictable pattern for forming the past tense: they simply add "-ed" to the base form (e.g., walk - walked, play - played).

* Irregular verbs have unique, often unpredictable past tense forms that don't follow this rule (e.g., go - went, see - saw, eat - ate).

There's no specific name for the verbs themselves; they are simply classified as irregular.