DICT.TW Dictionary Taiwan

 not to be sneezed at
 不可小看,不可等閒視之

 Sneeze v. i. [imp. & p. p. Sneezed p. pr. & vb. n. Sneezing.]  To emit air, chiefly through the nose, audibly and violently, by a kind of involuntary convulsive force, occasioned by irritation of the inner membrane of the nose.
 Not to be sneezed at, not to be despised or contemned; not to be treated lightly. [Colloq.] “He had to do with old women who were not to be sneezed at.”