Capricious:adjective: subject to, led by, or indicative of a sudden, odd notion or unpredictable change; erratic

Source: http://www.dictionary.com/browse/capricious

From: “The Shawl” by Louise Erdrich, page 5

“He became, for us, a thing to be avoided, outsmarted and exploited. We survived off him as if he were a capricious and dangerous line of work.”

Capricious is used to describe how the father of the protagonist behaves. The father’s excessive drinking has made him something to be feared by his own children because of his unpredictable behavior.