huiusmodi

Huiusmodi is two words welded together: huius, the genitive of hic, and modi, the genitive of modus. Literally "of this manner". Because it is frozen in the genitive it never changes shape, so it is indeclinable and agrees with nothing: huiusmodi verba, huiusmodi rebus, huiusmodi homini, all identical.

Classical Latin usually writes it as two words, huius modi, and prefers to place it after its noun. It has a full set of relatives built the same way: eiusmodi, "of that kind", cuiusmodi, "of what kind", istiusmodi. Medieval and legal Latin lean on huiusmodi heavily as a catch-all for "the said, the aforementioned", which is why English legal drafting still says "of this kind" where a plain writer would say "such". Talis is the ordinary classical alternative and is fully declinable.