free

1 a : relieved from or lacking something and especially something unpleasant or burdensome <free from pain> b : not bound or confined by force <upon opening the skull a considerable amount of free blood is noted—H. G. Armstrong>
2 a (1) : not united with, attached to, combined with, or mixed with something else <a free surface of a bodily part> (2) : having the bare axon exposed in tissue <a free nerve ending> b : not chemically combined <free calcium> c : not permanently attached but able to move about <a free electron in a metal>
3 : having all living connections severed before removal to another site <a free graft> <research…in free flap transfers—B. R. Alford>