The phrase "am fastened" implies being securely attached or restrained to something. Antonyms for this phrase can include "unfastened," "loose," or "free." To be unfastened means to be released from any physical restraint, allowing for movement without any obstacles. The opposite of being fastened is being loose, which implies a lack of binding or attachment, allowing for freedom of movement. Being free is a state of not being confined or restrained by anything, and doing what you want to do without anyone dictating your actions. All these antonyms convey a sense of mobility and lack of constraint that are the opposites of "am fastened.