あどけない (translations)→ boyish childish childlike endearingly innocence inviting juvenile little-girl
さりげなく (translations)→ absently careless carelessly casual casually casualness covert covertly delicately discreet discreetly effortlessly everyday inconspicuous matter-of-factly nonchalantly restrained simply unobtrusively unselfconsciously vague
なにげなく (translations)→ inadvertently indifferently lightly
屈託なく (translations)→ broadly cheerfully happily light-hearted
素直に (translations)→ decent dutifully easily genuinely gracefully honestly meekly passively serious straight straightforward unaffectedly