crackerjack

Etymology 1

From crack (“highly skilled, excellent”) + -er + jack (“man”).

adj

1. Exceptionally fine or excellent; top-notch; high quality.
2. Expert, top-rated or high-performing.

noun

1. An exceptionally fine or excellent thing or person.
2. An expert or top-rated individual (e.g., a marksman).

Etymology 2

From the trademark Cracker Jack popcorn snack featuring a blue sailor-suited man on the box.

adj

1. (US, slang) Referring to clothing items (pants, jersey, collar) that constitute the traditional blue uniform of the enlisted men of the US Navy.

noun

1. (US, slang, in the plural) The traditional blue uniforms of the enlisted men of the US Navy.
2. (US, slang) A U.S. Navy sailor.
3. (US, uncountable) Popcorn candied in molasses-flavored caramel and peanuts.
   "Here, here's the popcorn man," Sid said as a vendor passed, pushing a cart. Sid bought a package of crackerjack and opened it while Mickey jumped up and down, unable to wait. 1946, James T. Farrell, Bernard Clare, page 280