keen about, be

Idioms and Phrases

Be enthusiastic about. For example, He's been keen about this whole endeavor for a long time . It is also put as be keen on , which has the additional meaning “to be ardent about or in love with,” as in Jim's been keen on Jane for years . With other adverbs, such as keen at and keen of, keen has been so used since the early 1500s; the current locutions, however, date from the mid-1800s.