Inflection
For JA entries, we use ====Inflection==== for adjectives, and ====Conjugation==== for adjectives (which, in Japanese, function grammatically as a kind of stative verb).
The reason I've gone to using inflection is because the difference between declension and conjugation doesn't apply to every language or situation, while the term "inflection" is broad enough to fit. It's mostly an Indo-European centric distinction, and we're generally taught that declension applies to nominals and conjugation applies to verbs. That in itself is a silly distinction, since they are grammatically the same process, only the part of speech and the grammatical categories differ. But in Irish and Dutch, there are inflected prepositions; those don't fit into the declension-conjugation dichotomy.
We should follow what the existing entries do. Russian uses "Conjugation" for verbs and "Declension" for nouns and adjectives. IMO this distinction isn't silly; nor is using "Inflection" for both but we have to be consistent, otherwise the dictionary looks stupid and amateur (or more so than it already looks).