مُطْمَأَنٌّ
1.
A place of depression or lowness in the land or ground. (Mgh. [See also the following paragraph.])
2.
مُطْمَأَنٌّ إِلَيْهِ (tropical:) A thing to which one trusts, or upon which one relies, so as to become at rest or ease, or quiet, in mind. (S, K, * TA.)