Infinitive mood

Infinitive In*fin"i*tive, n. [L. infinitivus: cf. F. infinitif. See {Infinite}.] Unlimited; not bounded or restricted; undefined. [1913 Webster]

{Infinitive mood} (Gram.), that form of the verb which merely names the action, and performs the office of a verbal noun. Some grammarians make two forms in English: ({a}) The simple form, as, speak, go, hear, before which to is commonly placed, as, to speak; to go; to hear. ({b}) The form of the imperfect participle, called the infinitive in -ing; as, going is as easy as standing. [1913 Webster]

Note: With the auxiliary verbs may, can, must, might, could, would, and should, the simple infinitive is expressed without to; as, you may speak; they must hear, etc. The infinitive usually omits to with the verbs let, dare, do, bid, make, see, hear, need, etc.; as, let me go; you dare not tell; make him work; hear him talk, etc. [1913 Webster]

Note: In Anglo-Saxon, the simple infinitive was not preceded by to (the sign of modern simple infinitive), but it had a dative form (sometimes called the gerundial infinitive) which was preceded by to, and was chiefly employed in expressing purpose. See {Gerund}, 2. [1913 Webster]

Note: The gerundial ending (-anne) not only took the same form as the simple infinitive (-an), but it was confounded with the present participle in -ende, or -inde (later -inge). [1913 Webster]