A proxy war is a conflict involving the indirect or, at times, direct participation of third parties.
For instance, country A is in conflict with country B. To avoid direct confrontation, country A supports country C (its ally) in conflict with country D (an ally of country B).
It can also refer to a conflict instigated by a major power without its direct involvement.
Proxy wars enable major powers to avoid direct confrontation while advancing their interests in regions where they seek to maintain or expand their influence.