1. unwarranted; uncalled for
1. He's a pretty unpleasant character, and is known for offering gratuitous criticisms and insults.
2. Politicians expect all kinds of gratuitous favours and privileges wherever they go.
gratia (favour, grace) (Latin)
concise, succint, terse
GRE tution is not necessary. It's about common sense:P remember gratuity which is given freely to employee if they complete 5 yrs. or so in the company.