given, done, bestowed, or obtained without charge or payment; free; voluntary.

being without apparent reason, cause, or justification

a gratuitous insult.

Law . given without receiving any return value.

adjective

costly , expensive , deserved , needed , reasonable , warranted

adjective

chargeless , complimentary , costless , for nothing , gratis , spontaneous , unasked-for , unpaid , voluntary , willingnotes:grateful means feeling or showing gratitude or feeling thankful; gratified means having received what was desired; gratuitous means costing nothing or free - unnecessary or unwarranted - without cause , assumed , baseless , bottomless , causeless , groundless , indefensible , inessential , needless , reasonless , supererogatory , superfluous , uncalled-for , unessential , unfounded , unjustified , unmerited , unprovoked , unsupportable , unwarranted , wantonnotes:grateful means feeling or showing gratitude or feeling thankful; gratified means having received what was desired; gratuitous means costing nothing or free - unnecessary or unwarranted - without cause , supererogative