Which word is a synonym of the term 'conjugate' in grammatical terms?

In grammatical terms, "conjugate" refers to the way verbs change form to express different tense, mood, voice, aspect, person, number, or gender. This process involves altering the verb to correspond with the subject of the sentence and to fit various grammatical categories. "Decline" is closely related in that it often refers to the inflection of nouns, pronouns, and adjectives to show grammatical relationships such as case, number, and gender. While "conjugating" is specifically about verbs, "declining" is a broader term that includes changes made to other parts of speech, making it a suitable synonym in the context of grammatical transformations.

The other words presented do not convey the same grammatical concept: "separate" implies division, "join" suggests uniting elements, and "combine" denotes merging, none of which relate directly to the specific changes in form associated with verbs in grammar.