fitting · adjective, noun, verb1
From fit (“to conform to in shape or size; to be suitable for”, verb) + -ing (suffix forming present participles of verbs, and gerunds and nouns denoting the act of doing something or the embodiment of an action).
fitting · noun2
From fit (“to suffer a fit (‘convulsion, seizure’)”, verb) + -ing (suffix forming gerunds and nouns denoting the act of doing something or the embodiment of an action).
Etymology from Wiktionary, CC BY-SA 4.0.