Málfræðilegum
Málfræðilegum is an inflected form of the Icelandic adjective málfræðilegur, which means "grammatical" or "pertaining to grammar." In Icelandic, adjectives agree with the nouns they modify in gender, number, and case. The ending -um corresponds to the dative plural, so málfræðilegum is used before plural nouns in the dative case.
Examples of usage include phrases such as málfræðilegum spurningum (grammatical questions) or málfræðilegum reglum (grammatical rules)
Etymology and formation: the word is built from málfræði (grammar) plus the suffix -legur, which forms adjectives
Notes on usage: málfræðilegum is primarily encountered in formal or academic Icelandic, particularly in linguistics, grammar