Definitions for unstrained
Random House Webster's College Dictionary
not placed under psychological stress
"the campaign would not leave party loyalties unstrained"
not resulting from undue effort; not forced
"a voice with a pleasingly unforced quality"; "his playing is facile and unstrained"
not strained; not cleared or purified by straining; as, unstrained oil or milk
not forced; easy; natural; as, a unstrained deduction or inference