From Middle English hit-self, equivalent to it + -self.

• (RP, America, Canada) IPA: /ɪtˈsɛlf/
• (Australia) IPA: /ɪtˈself/

1. (reflexive pronoun) it; A thing as the object of a verb or preposition that also appears as the subject

   The door closed by itself

2. (emphatic) it; used to intensify the subject, especially to emphasize that it is the only participant in the predicate
   • 1638, Democritus Junior [pseudonym; Robert Burton], The Anatomy of Melancholy. […], 5th edition, Oxford, Oxfordshire: […] [Robert Young, Miles Flesher, and Leonard Lichfield and William Turner] for Henry Cripps, →OCLC ↗, partition II, section 2, member 6, subsection iv, page 298 ↗:

     Beautie alone is a ſoveraigne remedy againſt feare,griefe,and all melancholy fits; a charm,as Peter de la Seine and many other writers affirme,a banquet it ſelfe;he gives inſtance in diſcontented Menelaus that was ſo often freed by Helenas faire face: and ^hTully, 3 Tusc. cites Epicurus as a chiefe patron of this Tenent.

   The door itself is quite heavy.

3. (emphatic, archaic) it; used to refer back to an earlier subject

• itsself (obsolete)

• French: se
• German: von selbst, von allein, selbst, sich selbst
• Italian: sé
• Portuguese: se, a si mesmo
• Russian: -ся
• Spanish: se, solo, a si mismo, por si mismo

• French: soi-même
• Italian: se stesso, sé stesso
• Portuguese: ele/ela mesmo, próprio/própria
• Russian: оно сам
• Spanish: sí mismo, mismo