noun

1. A piece of knowledge that is hidden and intended to be kept hidden.

   “"Can you keep a secret?" "Yes." "So can I."”

2. The key or principle by which something is made clear; the knack.

   “The secret to a long-lasting marriage is compromise.”

3. Something not understood or known.

Synonyms: dern

verb

1. To make or keep secret.

2. To hide secretly.

   “He was so scared for his safety he secreted arms around the house.”

adjective

1. Being or kept hidden.

   “We went down a secret passage.”

2. Withdrawn from general intercourse or notice; in retirement or secrecy; secluded.

3. Faithful to a secret; not inclined to divulge or betray confidence; secretive, separate, apart.