not fastened together
"The loose button on his shirt was unattached and dangling freely near his elbow."
not associated in an exclusive sexual relationship
"She made it clear that she was unattached and open to seeing anyone who caught her interest at the singles mixer."
(of animals) able to swim about; not attached
"The unattached seal drifted helplessly away from the ice floe as the cold water closed in around it."
Not attached or joined; disconnected.
"The loose cable had become unattached from the wall outlet and was now dangling on the floor."