I. ˈkrakə(r)ˌjak noun
also crack·a·jack -kəˌj-
( -s )
Etymology: probably from crack (I) (to go fast) + -er + jack (fellow)
1. : an exceptionally skilled person
a good student and a crackerjack on the football field
the humor she was a crackerjack at — Saul Bellow
2. : a thing of highest excellence
a crackerjack of a book — Fitzhugh Green
II. adjective
also crackajack “
: of striking ability or excellence
a crackerjack revolver shot
a crackerjack bicycle