beteiligst
Beteiligst is not a standalone noun in German. It is the second-person singular present tense form of the verb beteiligen, which means to involve, to participate, or to share in. When used with a reflexive pronoun, as in du beteiligst dich, it means you participate or you take part in something. The verb can also take a direct object to indicate involving someone else, for example du beteiligst ihn an der Entscheidung (you involve him in the decision).
Grammatically, beteiligen is a regular verb. Typical forms include ich beteilige mich, du beteiligst dich, er
Usage notes: beteiligen is common in business, politics, and civil life to describe involvement or contribution.
Related terms include Beteiligung (participation, stake), Mitwirkung (participation/participatory role), and Teilhaben (to share in). The adjective