Simple past tense and past participle of sleek.(verb)
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Use "sleeked" in a sentence
"Unlike the production by Daniel Kramer, who neatly updated the action when he directed it a couple of years after the invasion of Iraq, Diane Paulus's Broadway production takes Gerome Ragni and James Rado's tale back to its henna'd roots, with the burning of draft cards, marching against the Vietnam war – "Lay, don't slay" – and domestic protest against parents who wore suits, sleeked their hair down, and Hoovered."
"Tall, dark, sleeked back hair, handsomely dressed in a double-breasted suit, he extended his hand."
"As he took off that awful cap, she saw immediately that the sleeked-down dark hair was a considerable improvement."