What is Calm ?
Calm is (adj) quiet, not rough or excited The sea was perfectly calm and no one was seasick. Keep calm, everything will be all right. Synonym tranquil. Antonym agitated (NOTE: calmer – calmest)(noun) a period of quiet The calm of the Sunday afternoon was broken by the sound of jazz from the house next door.(verb) to make someone, or a situation, more peaceful to calm down to make someone quieter; to become quieter and less annoyed She stroked his hand to try to calm him down. After shouting for some minutes he finally calmed down.
source: Easier English, Student Dictionary Upper Intermediate Level