Definition of mulls:
(v) :
(usually with over) To work (over) mentally; to cogitate; to ruminate.
(v) :
To heat and spice something, such as wine.
(v) :
To powder; to pulverize.
(v) :
To chop marijuana so that it becomes a smokable form.
(n) :
(uncountable) Marijuana that has been chopped to prepare it for smoking.
(v) :
To dull or stupefy.