Lilac

A lilac is a fragrant flower from Earth.

When the USS Defiant (2370) picked up Barry Waddle, he claimed Klingons stank. He didn't think about the fact that Worf was present; once Waddle was gone, O'Brien told Worf he liked the way the Klingon smelled, describing it as "sort of an earthy, peaty aroma," to which Bashir added, "with a touch of lilac."

Later, O'Brien tried to get one of the other senior staff members to benignly sniff the air around Worf and say, "Is that lilac?"

Varieties

 * Bajoran lilac