"Cancelled out" is a common phrase that describes the elimination or neutralization of something's effect or impact. There are several synonyms that can be used in place of "cancelled out" to convey this meaning. Some options include annulled, negated, nullified, offset, neutralized, and voided. These words all suggest a reversal or balance of some kind, where the original effect is negated or ignored. Other possible synonyms for "cancelled out" include negated, counteracted, invalidated, and balanced. Each of these words can be used to describe situations where opposing factors or forces are in play, or where one thing is used to offset or counter another.