Cheap.
Unambitious
No, it is not (despite the LY ending). The word costly is an adjective (expensive, high-priced).
There are several reasons why a natural, gem-quality diamond is costly, the foremost being it's rarity. Only about 20% of all diamonds mined are gem-quality. Also, lab-created diamonds are less costly that natural diamonds. Industrial quality diamonds are not costly.
Dear,costly and high-priced are some of the synonyms for expensive.
costly
Lame
Slave.
Unambitious
beleaguer
not funny
Regression.
fault
sry its fashionable
flowing or continous
The antonym for will is won't, i think. won't or will not
Benign circle
unpleasant pressure, unhappiness