Unkind means lacking any warmth towards somebody. An unkind remark, unkind to her, that was unkind.
It is a gentle-sounding word for a real fault, and in British use it is often the strongest thing said aloud: that was unkind does a lot of work. It describes acts and remarks more often than people. Note that kind once meant natural or of the same family — the same word as kin — so unkind first meant unnatural or disloyal to your own, which is a much heavier charge than the modern one.
1adjectiveunkindLacking any warmth towards somebody.
“It was unkind of you to laugh at her dress.”
synonyms: harsh, uncharitable
unkind is a quality of coldness.
Middle English unkynde is un- plus kind, and kind meant natural or belonging to the same kin. To be unkind was originally to act against your own family, which is where the modern sense softened from.
Middle English
unkynde
English, today
unkind
Middle English unkynde; equivalent to un- + kind.
Etymology from Wiktionary, CC BY-SA