synonymordbøker is the feminine plural indefinite of synonymordbok.

synonymordbokN

North Sámi

synonymasátnegirjiN

Norsk-nordsamisk ordbokdict-nob-sme/src/N_nobsme.xml:149657Edit on GitHub Suggest

Case	Sg	Pl
Indef	synonymordbok	synonymordbøker
Def	synonymordboken / synonymordboka	synonymordbøkene