Final answer:
Samuel Johnson's diction in the specified phrase is formal and reflective, typical of his time and often found in literary works to emphasize the passage of time.
Step-by-step explanation:
The word that describes Samuel Johnson's use of diction in the phrase 'seven years my lord have now passed' is formal and reflective. Johnson's language is characteristic of the period in which he wrote, often formal and elevated. The use of the phrase 'seven years' to measure time evokes a sense of reflection and passage of time, which is a common theme in literary works.