Rough, unkempt
Sleek generally means cool, shiny, smooth so the opposite would be something along the lines of gross or just plain messy.
Me and my hair are sleek today.
Sleek and gracefuf
The sports car had a sleek, aerodynamic design.
Sleek only has one syllable.
sleek (adjective) = מצוחצח (met-sookh-SAHKH)
Polished is another word for sleek. Additional synonyms include chic, shiny and glistening.
Here is an example sentence with the word "sleek":Melissa groomed her horse until its coat was sleek and shiny.
The machine looked sleek with a high build quality
The African Luhya translation of the English word 'Sleek' is "Eshiyakha".
An idiom is a phrase that makes no sense unless you know the definition. Sleek is a word.
The boy wasn't fat, he was sleek. Jim admired the sleek lines of the newest model Jaguar.
The word "sleek" in Spanish is "raso". It is pronounced "RAH-so". Please see this site for confirmation of the translation: http://www.answers.com/library/Translations