x1 (abstraction) bores x2 in manner x3; x2 is bired by/experiences boredom about x1, the boredom being of type/form x3.
There is debate in the literature about the nature of boredom; some believe that it is a sense of lack of meaning in what one is doing, others believe that it is just a lack of attentiveness about those tasks; other descriptions likely exist. As such, it feels inappropriate to construct this emotion, which feels rather atomic to me anyway, as a lujvo which picks one of these possibilities at the exclusion of others; its being a gismu will also allow it to be more easily used in other constructions. x3 is to specify the aforementioned nature, if it is identifiable or desired to be asserted; it can also be "existential" (ennui?) or similar.