To make something sleek or smooth, especially hair or fur.
Sleekened makes people think of beauty, style, and looking nice.
Examples:
She sleekened her hair before the party.
The cat sleekened its fur before going out.
He sleekened his tie before the meeting.
The dog sleekened its fur and looked very fancy.
The car was sleekened and looked like new.
The princess sleekened her dress and looked very pretty.