1. A method of categorizing nouns, pronouns, and adjectives regarding their number, their gender, and their grammatical cases: In English class at school, James learned about the declensions or formations of certain nominative forms of words, as with "man", "man's", "men", or "men's"; which he could then use correctly in his essay.

A grammatical case involves such declensions which are used to show their relations to other words: "I" is the nominative case; "me" is the objective case; and "my" is the possessive case.

2. A refusal or a rejection: The declension the teacher made prohibited the children from leaving the group at any time during their field trip to the state fair.
3. A decrease or a waning of something: A declension of Jack’s fitness was noticeable after being in the hospital for two weeks following the operation on his knee.
4. A slope or a downgrade: After climbing up the mountain and enjoying the view, the group's declension back to their cabin took several hours, but they arrived there before it was dark.