from the Star Trek: The Next Generation episode Birthright, part 1 (1993)
William Steig's book Shrek! was published in 1990.
There is more than a chance that Jaglom is named in part for the titular character of Steig's book, right?
From the Star Trek fan wiki Memory Alpha: "Braga coined the character's name from Henry Jaglom, an independent film director, and the old Yiddish word for "shriek". (Star Trek: The Next Generation Companion (2nd ed., p. 237))"
I do not believe everything I see on Memory Alpha, in part because that is a Fandom dot com Website. However, after some digging on Archive.org I managed to trace back the citation, which seems to be loosely paraphrasing Braga. This only confirms that Brannon Braga needs to answer some questions about Jaglom Shrek. Where did he get the name Shrek?
The Wikipedia page for the original children's book Shrek! says "The name 'Shrek' is the romanization of the Yiddish word שרעק (shrek), or שרעקלעך (shreklekh), related to the German Schreck and meaning 'fear' or 'fright'" For this information it cites an article which says just about the same thing in a lot more words.
I do not plan on spending any money to find answers to my Shrek questions, so unless I find more information about Steig's naming of Shrek! from before 1993 in a library this is likely the end of the line for my research.
From "Star Trek The Next Generation Companion" written by Larry Nemecek