Kiikoinen

Etymology
Possibly (because people from Kiikka may have been early settlers), or more directly from the name of the nearby rapids, which may be from  or.

Proper noun

 * 1) A former municipality in, Finland; now part of Sastamala.
 * 2) A village in the municipality of Sastamala.

Declension
Note that the inflected forms are formed as if they were plural.