1) Chemical irritant 
Isothiocyanate is the chemical group –N=C=S, formed by substituting the oxygen in the isocyanate group with a sulfur. Many natural isothiocyanates from plants are produced by enzymatic conversion of metabolites called glucosinolates. These natural isothiocyanates, such as allyl isothiocyanate, are also known as mustard oils. An artificial isothi...
The radical of isothiocyanic acid, -N==C==S. ... (05 Mar 2000) ... 
Type: Term Pronunciation: ī′sō-thī′ō-sī′ă-nāt Definitions: 1. The radical of isothiocyanic acid, -N=C=S.
[n] - a family of compounds derived from horseradish and radishes and onions and mustards
a chemical compound containing the univalent radical –NCS.