كنثبكَنْثَبٌ and كُنْثُبٌ and كُنَاثِبٌ Hard and strong: (K:) but the ث in this case is corrupted from ت: see كُنْتُبٌ in art. كنب. (TA.) كِنْثَابٌ [in the TA written كنابث] Sand  pouring down. (IAar, K.)