From Longman Dictionary of Contemporary EnglishSemtexSem‧tex /ˈsemteks/ noun [uncountable] trademark SCBa powerful explosive often used illegally to make bombs
Examples from the Corpus
Semtex• She remembered what the fat one had said about Mallachy's hands. Semtex.• They are jointly charged with conspiracy to cause explosions and possessing Semtex and six assault rifles on or before April 13. 