Not placed under psychological stress.

Roget 653: dirty, filthy, grimy; unclean, impure; soiled etc. v.; not to be handled with kid gloves; dusty, snuffy^†, smutty, sooty, smoky; thick, turbid, dreggy; slimy; mussy [U.S.].    slovenly, untidy, messy, uncleanly.    [of people] unkempt, sluttish, dowdy, draggle-tailed; uncombed.    unscoured^†, unswept^†, unwiped^†, unwashed, unstrained, unpurified^†; squalid; lutose^†, slammocky^†, slummocky^†, sozzly^†.    nasty, coarse, foul, offensive, abominable, beastly, reeky, reechy^†; fetid etc. 401.    [of rotting living matter] decayed, moldy, musty, mildewed, rusty, moth-eaten, mucid^†, rancid, weak, bad, gone bad, etercoral^†, lentiginous^†, touched, fusty, effete, reasty^†, rotten, corrupt, tainted, high, flyblown, maggoty; putrid, putrefactive, putrescent, putrefied; saprogenic, saprogenous^†; purulent, carious, peccant; fecal, feculent; stercoraceous^†, excrementitious^†; scurfy, scurvy, impetiginous^†; gory, bloody; rotting etc. v.; rotten as a pear, rotten as cheese.    crapulous etc. (intemperate) 954^†; gross etc. (impure in mind) 961; fimetarious^†, fimicolous^†.    ... show more

Roget 687: reposing etc. v. [of people]; relaxed etc. v.; unstrained.    [of materials and people] unstressed.   

Not resulting from undue effort; not forced:
— His playing is facile and unstrained.

synonym: unforced.