(Ex*pe`ri*en"tial*ism) n. (Philos.) The doctrine that experience, either that of ourselves or of that gained from others, is the test or criterion of general knowledge; — opposed to intuitionalism.

Experientialism is the philosophical theory of knowledge that sustains or acts as the outlook on life of many diversified stubbornly individualistic persons who prefer to think and decide  for themselves.

Experientialism allows one all of the  the notional freedoms of existentialism, which assumes that people are entirely free and thus responsible for what they make of themselves.

Experientialism is free of from mystical baggage of Platonic and Aristotelian folk philosophy, and the weirdo cultic  grammatico-ontological contortions and leader-worship of a Sartrean or Heideggerian cult-figure, which seems necessary for those bizarre philosophical sects.  
Experientialism rejects transcendentalist  sects and cults such as those epitomised by the throwback ontological aberration which is Existentialism.