zu-infinitive - Wiktionary, the free dictionary

From Wiktionary, the free dictionary

From German zu + infinitive.

zu-infinitive (plural zu-infinitives)

1. (grammar) a German infinitive form created by adding or infixing the particle zu and used in subordinate clauses

   abgeben → abzugeben

   vorbereiten → vorzubereiten

While theoretically any infinitive with zu could be considered a zu-infinitive (for example: haben → zu haben), this term is used primarily to refer to separable verbs with the zu particle infixed after the prefix.