From Dictionary.com:
learnt??/l?rnt/ [lurnt]
–verb
Active participle and past participle of learn.
learn?ed??/?l?rn?d for 1–3; l?rnd for 4/
–adjective
1. having much knowledge; scholarly; erudite: learned professors.
2. connected or involved with the pursuit of knowledge, esp. of a scholarly nature: a learned journal.
3. of or showing learning or knowledge; well-informed: learned in the ways of the world.
4. acquired by experience, study, etc.: learned behavior.