Meaning : Without cause.
Example :
A gratuitous insult.
Meaning : Costing nothing.
Example :
Complimentary tickets.
Free admission.
Synonyms : complimentary, costless, free, gratis
Meaning : Unnecessary and unwarranted.
Example :
A strikers' tent camp...was burned with needless loss of life.
Synonyms : needless, uncalled-for