In this movie https://www.youtube.com/watch?v=PNLnN8wLkg4 @00:01:30 the Klingon says: 'you're as week as a "quaHom" and there's no honor in killing a "quaHom" '. But what is "quaHom" ? From the context that word obviously names something weak, and it has the diminutive suffix -Hom, but I can't find that word in the Klingon dictionary. Could some one please help? Thanks.
I'm sure it was meant to be Qa'Hom and the actor just screwed up the pronuncition. Many uncoached English speakers add a "u" sound after "q", because in English we never use "q" without a following "u". In Klingon you can never have two vowels in a row, so "qua" cannot be Klingon. Qa'Hom is defined in Klingon for the Galactic Traveler as "type of animal (similar to a Qa', but smaller)".
He still doesn't actually get the word right, though, does he? It sounds to me like he mispronounced the "H".
What's the difference between "Qa'Hom" and "quaHom"?
The former is a word, and the latter isn't, in Klingon. There's a video of the actor who plays Gowron mispronouncing Qa'Hom so that it sounds like "quaHom", but that's a mistake.