synonyms:composed, collected, nonchalant, poised.Originally Posted by vhtan
antonyms: dispalying warmth and affection: warm, affectionate, caring, friendly, responsive.
This is what I would use when describing a person. I am not sure what you mean by express this sense in a document? Do you mean it's too informal? If so, I think you are right, we should avoid that one in formal writing.