jäykemmillä
The word "jäykemmillä" is the adessive plural form of the Finnish adjective "jäykkä". In Finnish, "jäykkä" translates to "stiff", "rigid", or "inflexible". The adessive case, indicated by the "-llä" ending, generally denotes being on, at, or with something. Therefore, "jäykemmillä" signifies "with stiffer ones" or "on stiffer ones".
When "jäykemmillä" is used in a sentence, it implies a comparison. The "-mpi" suffix is the comparative
For example, one might say that a certain material is "jäykemmillä" components, meaning it is constructed with