inhibited
adj
(a) (of people) unable to relax or express one´s feelings in a natural and spontaneous way (指人)拘谨的, 不能自然表达感情的
She´s too inhibited to laugh at jokes about sex. 她很拘谨, 听到性爱笑话也不笑.
(b) (of behaviour) not relaxed or spontaneous (指举止)不轻松的, 不自然的
a nervous inhibited laugh 紧张而矜持的笑.