strident

Short definition from Wiktionary

Adjective

1. 1
   Loud; shrill, piercing, high-pitched; rough-sounding.
2. 2
   Grating or obnoxious.
3. 3
   Forceful (typically in a negative way) or obtrusive.
4. 4
   Vigorous; making strides; forceful in a positive way.

Noun

1. 1
   One of a class of s-like fricatives produced by an airstream directed at the upper teeth.