Yes, it can: it means someone who has studied a great deal and now knows a lot about a subject(s). However, it should only be used before a noun, not after it, e.g., "He is a very learned man" (not "She is learned"). Also, when we used this word as an adjective, the pronunciation changes from one syllable to two syllables, and the accent/stress falls on the first syllable: LEARN-ed.

Yes, it can. www.thefreedictionary.com/learned