Giac (pronounced jăk) has always done his best to keep his personal history private, so nothing is known of his family or upbringing. However, it is known that his two great passions in life have always been humor and knowledge. He's a great lover of reading, and is said to have spent most of his childhood in libraries. It is unknown if he ever had a master or masters, growing up, but at the age of 21, he began a career as an independent master of both history and literature. During the latter years of the Coming of the Order, he was one of the most vocal supporters of the suggestion of a standardized school system, and when the first grade school in his village opened in 904, he became its headmaster. It was just a bit later that year that he became the newest chairperson of the Experimental Linguists' Club, of which he had been a member for over a decade. It is because of his love of words (and in particular, subwords) that when the surname law was passed that year, he chose the name 'Thesaurus.'
And then, quite unexpectedly, in early 905, he quit his job as headmaster of his school, accepting a job offer from the newly-inaugurated King Demos Royal, as a "royal clown." It is known that at some point during the Coming, Giac and Demos had met and become friends, though the precise details of how they met are unknown. Giac was a supporter of Demos during his campaign for monarch, though no one really expected them to have much contact with each other after the 904 election, let alone expect Giac to make such a drastic career change. Some people would later suggest that the choice was related to his obvious interest in synonyms, as well as history. It was known that on Earth, there was once a job known as 'court jester,' which is essentially what Demos meant by 'royal clown.' While this is perhaps somewhat different from the clowns of circuses, it is thought to be somewhere between such clowns and more modern 'comedians.' Comedians have, in the last century or so, been trying to distinguish themselves from clowns, though most people still use the term 'clown' to refer to both professions, while the term 'comedian' is rarely used by non-comedians. Giac himself has become a vocal part of the effort to change people's vocabulary in this matter, though most comedians apparently do not appreciate his help. They tend to disdain his acceptance of the term 'clown' for his own job, as well as the fact that his job requires him to dress as a clown, in costume and makeup, for the king's amusement. In spite of this, the majority of his job consists of telling jokes, rather than engaging in pratfalls or other circus antics.
While some believe Giac accepted the job to put him in a position to influence more people's thinking than he could as a local headmaster, there are others who insist he must have endured some kind of trauma to make him give up a serious and respectable career as an educator. However, because of how closely he guards his private life, no one has any guesses as to the nature of this speculative trauma. Still others think the career change was caused by a 'midlife crisis,' or perhaps simply a desire for a less stressful life, or a refocusing on his love of humor, which it is suggested he neglected for many years in favor of his love of learning.