guesstimate

the word 'guesstimate' is a modern portmanteau, a blend of the english words 'guess' and 'estimate'. it first appeared in the early 20th century, primarily in american english. the term humorously and candidly acknowledges the inherent uncertainty in many calculations, combining the informal, intuitive nature of a 'guess' with the more formal, numerical connotation of an 'estimate'. its formation follows a common pattern in english for creating new words that fill a semantic niche, in this case, describing an approximation that is partly informed and partly conjectural.

Structure: guess + (e)stimate guess (middle english, from old english 'gessen', meaning to estimate, judge) + estimate (latin 'aestimatus', past participle of 'aestimare', meaning to value, appraise)