(1):

(a.) Younger or inferior in rank; junior; associate; as, a chief justice and three puisne justices of the Court of Common Pleas; the puisne barons of the Court of Exchequer.

(2):

(n.) One who is younger, or of inferior rank; a junior; esp., a judge of inferior rank.

(3):

(a.) Later in age, time, etc.; subsequent.

(4):

(a.) Puny; petty; unskilled.