What is a word for someone that speaks their mind even if it hurts someone's feelings?

There are several choices:

boorish

tactless

narcissistic

thoughtless

arrogant

judgemental

If the one hurt is someone in authority who has been neglectful and needs to hear some tough feedback, then the speaker might be thought of as:

fearless

principled

There are many variations if you consider the speaker, the situation, all the individuals present, and the motivationof the speaker. If a person has noble intentions but is a bit bungling, that will look and feel much different from a person who takes pleasure in seeing others hurt.

It takes a rare degree of subtlety and tact to be able to tell the truth and do it in a way that is not hurtful. A few can do it humorously, and that's a special gift. Honesty is always good, but hurtfulness is rarely necessary and is not often helpful.