Is jackleg a word in the Scrabble Dictionary

Yes, jackleg is playable

...and is worth 26 points.

Found in the following dictionaries

Enable (Words with friends)
SOWPODS (Collins Scrabble Words)
OTCWL2014 (NASPA Word List 2014)
TWL06 (NASPA List 2006)

"Jackleg" Definition

noun

A strikebreaker.
An unskilled or unscrupulous itinerant worker.

adjective

Lacking skill or training; incompetent. Used especially of lawyers or preachers.
Makeshift; temporary.
Unscrupulous or dishonest.
Characterized by unscrupulousness, dishonesty, or lack of professional standards .
Lacking skill or training .