The dispatches […] also exposed the blatant discrepancy between the west's professed values and actual foreign policies. Having lectured the Arab world about democracy for years, its collusion in suppressing freedom was undeniable as protesters were met by weaponry and tear gas made in the west, employed by a military trained by westerners.
Meaning of suppressing for the defined word.
Grammatically, this word "suppressing" is a noun, more specifically, a countable noun. It's also a verb, more specifically, a verb form.