complimentary

adjectives

conveying or resembling a compliment
"a complimentary remark"
is derived from
antonym
is similar to
formally expressing praise
is similar to
full of or giving praise
"a laudatory remark"
see also
encouraging or approving or pleasing
"a favorable reply"; "he received a favorable rating"; "listened with a favorable ear"; "made a favorable impression"
costing nothing
"complimentary tickets"; "free admission"