Definition of "chem"

(uncountable, university slang, often capitalized) Clipping of chemistry (“branch of natural science”); usually referring to the subject or the department.  quotations

(countable, informal, often in the plural) Clipping of chemical.  quotations

1. A chemical weapon.  quotations  examples

   Quotations

   • This is the very opposite of what we’ve called for — namely, for Biden to publicly identify in advance a specific US (at least) hard-power response to Putin’s use of chems (or other weapons of mass destruction).

     2022 March 24, “Biden press conference gives Putin less than nothing to fear”, in New York Post‎

2. A recreational drug.  quotations  examples

   Quotations

   • “I actively searched for someone to tell me how they’d made an informed and calculated choice to use chems and, that for them, the chem scene is just recreation.” […] “Even those who told me sex on chems made them feel ‘like a don’ would follow up such celebratory statements with tales of rejection, regret, loneliness and longing for intimacy,” he said.

     2016 May 10, Ben Guarino, “The ‘chemsex’ scene: An increasingly popular and sometimes lethal public-health problem”, in The Washington Post‎

   • When you think ‘drugs’, you think Trainspotting. ‘Chems’ is easier off the tongue and, although explicit, it doesn't feel quite as bad. At least to us.

     2017, James Wharton, Something for the Weekend‎, Biteback Publishing

(informal) Clipping of chemical.  quotations  examples