must-
combining form
indicating that something is highly recommended or desirable
⇒ 
a must-see film
⇒ 
this season's must-haves
must-
                combining form
     -          used to form adjectives denoting things that are essential or highly recommended[构成形容词]表示“必不可少(或强烈推荐)的事物”:
-       must-have a must-read book. 
ORIGIN: from must  verb