deepen
UK: ˈdiːpən | US: ˈdiːpən
vt. to make or become deeper
vi. to increase in depth or intensity
The word "deepen" combines the adjective "deep" (from Old English "dēop," meaning "extending far down") with the verb-forming suffix "-en," which originates from Old English "-nian." This suffix transforms adjectives into verbs, implying "to make or become [adjective]." The logical progression is straightforward: "deep" (a quality) + "-en" (action) = "to make deep." Historically, "-en" was productive in forming verbs from adjectives (e.g., "sharpen," "brighten"), and "deepen" follows this pattern, first recorded in the 16th century.
The diver used weights to deepen his descent.
Their conversation deepened their understanding of the issue.
The shadows deepen as the sun sets.
The government plans to deepen the river for larger ships.
Her frown deepened when she heard the news.