Elle est vraiment amicale - She is very friendly.
Il est peu amical - He's not very friendly.
Related: une amicale - association, club
un ami, une amie - friend
amicalement - in a friendly way
Have you ever received a letter from a French speaker signed "friendly"? This common mistake was made famous by French president François Hollande in a letter dated 7 November 2012 to American president Barack Obama. "Friendly" is one of the few English words that ends in -ly but is not an adverb - it's just an adjective. Since the logical adverb, "friendlyly," is clearly nonsense, we're left with the clumsy translation "in a friendly way" or the oddly stilted "in friendship." The feeling of amicalement could in theory be translated by "your friend," but since that has a definite grade school sort of feeling, it's better to choose one of the translations above.
Another common mistranslation at the end of personal letters is "friendships" for amitiés.
(click the little graphic below to hear the Mot du jour pronounced)