As a general rule, capitalize an adjective derived from a proper noun or a name used adjectivally:
Proper adjectives are associated with the person or place from whose name they are derived. When this association is remote, the adjective becomes common and in most cases no longer takes a capital, as illustrated below:
Verbs derived from proper nouns are also capitalized unless their association with the proper noun is remote:
Check proper noun derivatives carefully, however. Usage in this regard is not standardized.
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TERMIUM Plus®, the Government of Canada's terminology and linguistic data bank
Writing Tools – The Canadian Style
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