Word for someone who says exactly what they are thinking [closed]

Forthright is a word which describes someone who says exactly what they are thinking.

'free in expressing one's true feelings and opinions'

Merriam-Webster

George Orwell's contention was that it is a sure sign of trouble when things can no longer be called by their right names and described in plain, forthright speech. . . . Christopher Lasch

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One adjective that might work is unfiltered, which Merriam-Webster's Eleventh Collegiate Dictionary (2003) defines as follows:

unfiltered adj (ca 1775) 1 : not filtered {unfiltered wine}; also : not modified, processed, or refined {unfiltered commercial publicity material —Paul Grimes} 2 : lacking a filter {an unfiltered cigarette}

As the Eleventh Collegiate notes in its definition of filter, that word can refer to

something that has the effect of a filter (as by holding back elements or modifying the appearance of something

A person who has no internal check on his or her thoughts and thus holds back nothing of what he or she is thinking may thus be described as unfiltered.