忍しのびやか

na-adjective, noun

stealthy; secret; quiet and unobtrusive

Describes actions or manner that are done quietly so as not to be noticed; often used with verbs like 動く, 近づく, or 去る.

• 忍しのびやかに部屋へやを出でた。

  I left the room stealthily.

• 忍しのびやかな足あし音おとが廊ろう下かから聞きこえた。

  I heard quiet, stealthy footsteps from the hallway.