"he could feel the slickness of the tiller"

"sidewalks slick with ice"
"roads are slickest when rain has just started and hasn't had time to wash away the oil"

"glib promises"
"a slick commercial"

"glossy auburn hair"
"satiny gardenia petals"
"sleek black fur"
"silken eyelashes"
"silky skin"
"a silklike fabric"
"slick seals and otters"

"cunning men often pass for wise"
"deep political machinations"
"a foxy scheme"
"a slick evasive answer"
"sly as a fox"
"tricky Dick"
"a wily old attorney"

"slick one's hair"