think nothing of it

:  to form or have in the mind

:  to have as an intention

:  to have as an opinion

:  an act of thinking

:  relating to, requiring, or stimulating thinking

:  not any thing :  no thing

:  no part

:  one of no interest, value, or consequence

:  not at all :  in no degree

:  something that does not exist

:  the absence of all magnitude or quantity

:  zero

:  of no account :  worthless