gratuitous (adj.)

• aimless
• allowed
• amorphous
• arbitrary
• autonomous
• baseless
• bluff
• bottomless
• brash
• capricious
• casual
• charitable
• cheeky
• cocky
• complimentary
• contemptuous
• costless
• crusty
• derisive
• desultory
• discontinuous
• discretional
• discretionary
• disjunct
• disordered
• dispensable
• dispersed
• disproportionate
• disrespectful
• elective
• eleemosynary
• erratic
• excess
• expendable
• fitful
• flip
• flippant
• formless
• free
• fresh
• frivolous
• given
• granted
• gratis
• groundless
• haphazard
• hit-or-miss
• impertinent
• impudent
• inchoate
• incoherent
• indefensible
• independent
• indiscriminate
• irrational
• irregular
• meaningless
• misshapen
• needless
• nervy
• nonessential
• nonmandatory
• nonuniform
• optional
• pert
• planless
• pleonastic
• prolix
• promiscuous
• providential
• random
• reasonless
• redundant
• rude
• sassy
• saucy
• self-acting
• senseless
• shapeless
• smart
• spare
• spasmodic
• spontaneous
• sporadic
• straggling
• straggly
• supererogatory
• superfluous
• tautologic
• unasked
• uncalled-for
• unclassified
• uncoerced
• undirected
• unessential
• unforced
• unfounded
• ungraded
• uninfluenced
• uninvited
• unjustifiable
• unjustified
• unlooked-for
• unmethodical
• unnecessary
• unneeded
• unordered
• unorganized
• unprompted
• unrequested
• unsolicited
• unsorted
• unsought
• unsupportable
• unsymmetrical
• unsystematic
• untaxed
• unwarranted
• unwelcome
• vague
• verbose
• voluntary
• volunteer
• wandering
• wanton
• willful
• willing