From en.wiktionary.org:
** English
*** Etymology
From [en].
*** Verb
[en-verb]
1. [en] To make more slender .
2. * {{ quote-journal | en | date=July 26, 2009 | author=Lawrence Ulrich | title=A Redesign Aims Lower and Yet Comes Up Short | work=New York Times | url=http://www.nytimes.com/2009/07/26/automobiles/autoreviews/26cadillac.html
|passage=There’s no sugar-coating it: this direct-injection V-6 seems a
compromise, a SLENDERIZED version of the CTS’s 3.6-liter.}}
1. * {{ quote-text | en | year=2011 | author=Amy Cotta | title=Six Weeks to Skinny Jeans | page=10
|passage=You will sequence through upper and lower-body exercises that are
designed to lift, reduce, and SLENDERIZE your hips, thighs, and booty while
giving you sleek, sexy arms!}}
1. * {{ quote-text | en | year=2012 | author=Rebecca Apsan | title=Lessons in Lingerie: Finding Your Perfect Shade of Seduction
|passage=When dressing up for a night out, let's not forget the sex appeal,
allure, and SLENDERIZING effect of ultrasheer black hosiery under that little
black dress.}}