In a manner relating to or characteristic of an epiphenomenon; as a secondary effect without causal influence.
From epiphenomenal + -ly (adverbial suffix). This adverb describes how something operates or occurs as a mere byproduct or incidental effect.
If something happens epiphenomenally, it's basically hitching a free ride on the actual causal process—present but powerless to steer the ship!
Complete word intelligence in one call. Free tier — 50 lookups/day.