What part of speech is indorse?

Indorse can be categorized as a verb.

Parts of speech

1. indorse is a verb, present, 1st person singular of indorse (infinitive).
2. indorse is a verb (infinitive).

Verb
indorse - be behind; approve of; "He plumped for the Labor Party"; "I backed Kennedy in 1960"
indorse - give support or one's approval to; "I'll second that motion"; "I can't back this plan"; "endorse a new project"
indorse - guarantee as meeting a certain standard; "certified grade AAA meat"
indorse - sign as evidence of legal transfer; "endorse cheques"