无动于衷aloof;indifferent;unconcerned

无价之宝an object that is priceless or an asset (can also refer to abstract things)

无精打采dispirited and downcast;listless;in low spirits;washed out

无可奉告“no comment”

无可奈何have no way out;have no alternative

无理取闹to make trouble without reason;deliberately awkward;pointless provocation;willful trouble maker

物美价廉cheap and fine;attractive in price and quality

无能为力impotent;powerless;helpless

无穷无尽vast and limitless;endless span of time;no vestige of a beginning;no prospect of an end

无微不至in every possible way;meticulous