تهرتَاهُورٌ [probably, in its primary acceptation, a dial. var. of تَيْهُورٌ; for the signification here following is said in the TA to be tropical: b2: ] (tropical:)  Clouds; or a collection of clouds: (JK, K, TA:) pl. تَوَاهِيرُ. (JK.) تَيْهُورٌ, said by Az to be of the measure فَيْعُولٌ, from الوَهْرُ; originally وَيْهُورٌ, like as تَيْقُورٌ is [said to be] originally وَيْقُورٌ; but the ت is held by ISd [and J and F and others] to be a radical: (TA:) Low, or depressed, sand: (T, TA:) or sand that falls apart, and does not hold together: (A, TA:) or elevated sand: (TA:) or sand having a جُرُف [or part carried and eaten away by torrents]: (As, S, K:) pl. تَيَاهِيرُ and تَيَاهِرُ. (S, K.) b2:  Low, or depressed, land, or ground. (K.) b3:  The part between the top and bottom of the side of a valley, and of a mountain: (JK, K, * TA:) of the dial. of Nejd, and of that of Hudheyl. (TA.) b4:  High waves of the sea or of a great river. (K.) b5:  Applied to a man, [like تَيَّارٌ, q. v.,] (assumed tropical:)  Vain, or having a fond opinion of himself, (S, K,) and proud. (K.) [For ذَاهِيًا in one copy of the S, and ذَاهِبًا in another and in the L, in the phrase إِذَا كَانَ ذَاهِيًا بِنَفْسِهِ بِهِ تِيهٌ, or ذَاهِبًا, I read زَاهِيًا.]