1) An annoying person or thing; a nuisance.
2) An injurious plant or animal, especially one harmful to humans.
3) A deadly epidemic disease; a pestilence.
Very human-centric, but since the language used is a human invention, I suppose this can be forgiven. If a pest is a "nuisance," is that enough reason to reach for a can of pesticide? Whether the creature is an annoyance or a carrier of pestilence, in the grand scheme of things, "pest" is clearly a subjective observation.
At our home of the future, I've talked the ants mostly into the walls. The spiders, however, are resisting me. Perhaps because I fear them. I have a jar that I use sometimes to collect them and put them outside. In my bathroom and bedroom, I collected 27 spiders one day, gently shaking them out into the backyard. It took me about 20 minutes. Note: spiders are very fierce with each other, so if you should choose to do catch and release instead of using a Bug Vacuum, collect them one at a time. If training pit bulls to battle is wrong, then surely putting two spiders together for a death match is too.
I'm becoming more and more non-judgmental. Knowing that defining a creature as "pest" is a judgment, I am free to co-exist with the other dwellers in my house.
Even the creepy ones.