形容词

1. 赞美的;赞扬的
If you are complimentary about something, you express admiration for it.

2. (座位、票或书)免费赠送的
A complimentary seat, ticket, or book is given to you free.

1. conveying or resembling a compliment

e.g. a complimentary remark

2. costing nothing

e.g. complimentary tickets
free admission

Synonym: costlessfreegratis(p)gratuitous