[W/K] :: 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]