There is something of medieval whimsy in the sound of the word. Playful, it could be a village child’s name. “Come hither, Tansy, tarry ye not,” perhaps.
But it is not that common a name at all.
Perchance there is a darkness carried in the first syllable, where the stress falls. And this would be fitting, for tansy was once strewn on graves and woven into funeral shrouds to help preserve the body. One possible origin of the genus name Tanacetum comes from the Greek word athanasia (ἀθανασία), meaning “immortality”.
You will see the green fronds growing lush beside paths and in open places, such as the parking at Hoppinpunt, soon to hold bright yellow buttons aloft which persist well into midwinter.
I read that there is a contemporary composer named Tansy Davies. One of her works is called Forest.