قامسهُ

, (K,) verbal noun مُقَامَسَةٌ, (TA,) He vied, or contended, with him in diving. (K, * TA.) You say, ↓ قَامَسَتُهُ قَقَمَسْتُهُ, (S,) [aorist of the latter, according to rule, قَمُسَ only,] verbal noun قَمْسٌ, (K,) I vied, or contended, with him in diving, (TA,) and I overcame him therein. (K, TA.) You say of him who contends, disputes, or litigates, with an adversary, (A,) or who disputes with one more knowing than himself, (S, K,) فُلَانٌ يُقَامِسُ حُوتًا (tropical:) [Such a one vies, or contends, in diving with a fish]. (S, A, K.) You say also, فُلَانٌ يُقَامِسُ فِى سِرِّهِ, meaning, (assumed tropical:) Such a one hides himself at one time and appears at another. (TA.)