When you skip, you do a little hop from foot to foot as you move along. It's pretty common to see little kids skip down the sidewalk or across the playground.
While a happy, running hop is one kind of skip, you can also use this verb to mean "pass up" or "pass over." You might arrive late to the movies and skip the trailers at the beginning, or skip the bread basket at a restaurant so you have room for dessert later. The earliest meaning of skip, from the 1300's, is "to spring lightly," from the Old Norse root word skopa.