Green’s Dictionary of Slang

1. (Aus., also chalkie) a schoolteacher.

1953		T.A.G. Hungerford Riverslake 29: ‘I was a chalky before the war.’ [...] ‘Chalky?’ ‘School-teacher.’.
1972		A. Chipper Aussie Swearers Guide 65: Chalkie (also Schoolie). School teacher.
1999		G. Seal Lingo 76: A few farther examples: [...] chalkie – teacher. Closely related to the last is schoolies – nowadays usually applied to schoolchildren, though it may also be used to include teachers, a usage dating from at least the late 19th century.

2. (Irish) a pavement artist.

1991

K.C. Kearns Dublin Street Life and Lore 213: He is one of the most gifted ‘chalkies’ on Dublin’s streets.