luminescen
Lets arrange the letters alphabetically = ceeilmnnsu
Words starting with c = 9!/(2!*2!) = 90720
Words starting with e = 9!/(2!) = 181440
Words starting with i = 9!/(2!*2!) = 90720
Words starting with lc = 8!/(2!*2!) = 10080
Words starting with le = 8!/(2!) = 20160
Words starting with li = 8!/(2!*2!) = 10080
Words starting with lm = 8!/(2!*2!) = 10080
Words starting with ln = 8!/(2!) = 20160
Words starting with ls = 8!/(2!*2!) = 10080
Words starting with luc = 7!/(2!*2!) = 1260
Words starting with lue = 7!/(2!) = 2520
Words starting with lui = 7!/(2!*2!) = 1260
Words starting with lumc = 6!/(2!*2!) = 180
Words starting with lume = 6!/(2!) = 360
Words starting with lumic = 5!/(2!*2!) = 30
Words starting with lumie = 5!/(2!) = 60
Words starting with luminc = 4!/(2!) = 12
Words starting with luminec = 3! = 6
Words starting with luminee = 3! = 6
Words starting with luminen = 3! = 6
Words starting with luminescen = 1