There are times when you feel… keckish. Your throat feels like one of those hard hollow plant stalks, or a pants leg dipped in saltwater and dried out, rigid, astringent. It is as if someone has stuck a popsicle stick too far back in your gullet. You can’t kick it; you keck, keck, keck!
Keck, verb, means ‘gag’ as in ‘try not to vomit but not have an easy time of it’. It can be used figuratively (with at) to refer to expression of disgust: “Ugh. I keck at that jackass’s expectorations.”
Keckish means ‘inclined to keck’; it’s disused but useful, and has a synonym kecklish.
Kecks plural can refer to pants: in Scotland and northern England, your kecks are your trousers, and if you’re caught with your kecks down, you’re in an embarrassing spot. That usage comes from kicks, as far as we can tell.
Kecks seems not to have to do with kex, also seen as keck, which like pants legs is tubular but is harder and smaller – it’s a hard hollow stalk of an umbelliferous plant such as cow parsnip, wild chervil, or marsh angelica (as Oxford tells me). The x may lead you to expect a Greek origin, but no, not as far as we can see. On the other hand, we don’t quite know just what lexical marsh it did sprout out of.
What a keck-collection! It’s nothing to cough or scoff at; it kexceeds kexpectation (but not kexpectoration).
So. If the sight or sense of a strawlike stem in his dungarees makes a fellow gag, that means he kecks at kex in his kecks… just for kexample.