x1 is a (Lojban) root word expressing relation x2 among argument roles x3, with affix(es) x4.
This word is meant to have exactly the same meaning, notes, restrictions, associations, etc. as gismu; the two words are intended to be identical in every way except for four- and five-letter rafsi (and the obvious phonetic/spelling difference). The cmarafsi for this word are "-gim-" and "-gi'u-". Etymologically, this word should have been chosen rather than gismu (according to the CLL (see the gismu creation algorithm): https://lojban.github.io/cll/4/14/ step #5), but there was an error in the input/transcription; however, due to gimkamsmikezypro, these two forms are identical in meaning and every other important characteristic or property or endowment, excepting associated rafsi options; the preferred version of all members of the "gismu" quotient/equivalence class (presently "gismu" itself) determines the potential or actualized rafsi associated with that class; in this case (between "gicmu" and "gismu"), only the longer rafsi are affected (no cmarafsi of "gismu" use the "s").