Sibilant

a.

1.

Making a hissing sound; uttered with a hissing sound; hissing; as, s, z, sh, and zh, are sibilant elementary sounds.

Noun	1.	sibilant - a consonant characterized by a hissing sound (like s or sh) Synonyms: sibilant consonant
Adj.	1.	sibilant - of speech sounds produced by forcing air through a constricted passage (as `f', `s', `z', or `th' in both `thin' and `then') Synonyms: fricative, spirant

fricative, soft, spirant