Sleeping outside in the backcountry without an overhead shelter (such as a tent or tarp), usually done in the context of backpacking. The decision to cowboy
camp is a calculated
one - bugs, rain, snow,
etc. are all possible backfires to the decision and can damper the experience.
Note that having an adequate shelter is a must, cowboy
camping is the decision to forgo setting up a dedicated shelter and betting that conditions will be such that the shelter is not needed (but the dedicated shelter is
still present/available should it be needed). Not bringing adequate shelter with you into the backcountry is foolish and can result in injury or death.