Terminology in graph theory

The condition says that a subgraph induced by 3 vertices cannot have exactly one edge. The graph with three vertices and exactly one edge is $\overline{P_3}$, where $P_3$ denotes the path on three vertices. Graphs that do not have a particular graph $H$ as an induced subgraph are often called $H$-free graphs. So, these graphs are $\overline{P_3}$-free graphs.

As observed in the comments, complete multipartite graphs are $\overline{P_3}$-free. In fact, it is not hard to show that a graph is $\overline{P_3}$-free if and only if it is complete multipartite or an empty graph.