Guessume 

Guessume (or guessumption) is a combination of guessing and assuming.

I guessume you bought us dinner?

Guessume by KC Rappa November 4, 2016

guessometer 

The range indicator on the instrument cluster of an electric car, particularly Nissan Leaf. It is called a guessometer due to its inability to provide a reliable number for the remaining range of the electric car.

The guessometer dropped to 40 miles just after 10 miles driving.

guessometer by MiKeEchoSierra February 17, 2019

guessumption

for use when relaying information that is part Guess part Assumption.

Well mike, I would have to make a guessumption, it will take approximatly 5 hours to complete that job

guessumption by Nathan Snow November 14, 2006

guessumption

Assuming and guessing something at the same time.

When he tried to solve the math problem he made a guessumption.

guessumption by Angriest Mouse of Schnaasberg November 3, 2021