Refers to simple or rudimentary pictures (drawings, paintings, etc) of people. They're called "matchstick men" because their limbs are made of simple lines, or matchsticks.
Con artists are also referred to as matchstick men because they create temporary personas that are fleeting and simple.
Dude, don't give that guy any money. His story doesn't add up. He's totallyjust a matchstick man.
Many a L. S. Lowry painting includes a matchstick man.
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.