When I first heard the word "travelocity" I thought it was a clever combination of two existing words ("travel" + "velocity") that yielded a new and meaningful word. I wondered how difficult it would be to come up with more clever words like "travelocity". Invent-a-Word was born. The best portmanteau word I've come up with so far is cubicle + cleaner = cubicleaner.
Your creative words:
sadness + essay
= sadnessay
sadness + essayed
= sadnessayed
sadness + essayer
= sadnessayer
sadness + essays
= sadnessays
sadness + essence
= sadnessence
sadness + essence's
= sadnessence's
sadness + essences
= sadnessences
sadness + essential
= sadnessential
sadness + essentially
= sadnessentially
sadness + essentialness
= sadnessentialness
sadness + essentials
= sadnessentials