themselves

themselves /ðɛmˈsɛlvz/ pronoun
themselves
/ðɛmˈsɛlvz/
pronoun
Britannica Dictionary definition of THEMSELVES
1 
: those same people, animals, or things:
a  — used as the object of a verb or preposition to refer to people, animals, or things that have already been mentioned
b  — used for emphasis to refer again to people, animals, or things that have already been mentioned
2 
: himself or herself — used to refer to a single person whose sex is not known or specified
3 
: their normal or healthy selves

by themselves

1 
: without any help from other people
2 
: with nobody else : alone