1. (a.) Reciprocally acting or related; reciprocally receiving and giving; reciprocally given and received; reciprocal; interchanged; as, a mutual love, advantage, assistance, aversion, etc.

2. (a.) Possessed, experienced, or done by two or more persons or things at the same time; common; joint; as, mutual happiness; a mutual effort.

accessory accompanying associated attendant attending changeable coacting coactive coadjutant coadjuvant coefficient coincident collaborative collateral collective collectivist collectivistic collusive combined commensal common communal communalist communalistic communist communistic communitarian commutable commutative commutual complementary concerted concomitant concordant concurrent concurring conjoint conjunct connected conniving convertible cooperant cooperating cooperative correlative coupled ecumenic equal equalizing equivalent even exchanged fellow general give-and-take harmonious harmonized in common interactive interchangeable interchanged joined joint noncompetitive paired parallel permutable popular public reciprocal reciprocating reciprocative related respective retaliatory returnable shared simultaneous social socialistic societal standard swapped switched symbiotic synergetic synergic synergistic traded transposed twin two-way uncompetitive united