-wijs

Etymology
See.

Suffix

 * 1) -wise;

Usage notes

 * As these compounds essentially represent univerbations of genitive absolute phrases (e.g. spelender wijs "in a playing manner" -> ), the preceding adjective or participle requires the feminine genitive singular ending  (as  is feminine and the preceding adjective or participle must be congruent with it).
 * As the genitive is not in use anymore in modern Dutch (except vestigially) and has been only dimly known among the general public since the second half of the twentieth century, new words with this suffix contain the genitive ending -er not because they represent a genuine univerbation of a previously separate genitive absolute phrase, but because they are derived by analogy with other words formed in this way.