Deprecatingly
/ˈdeprəkeɪtɪŋli/
Definition 1 of 1
Pro Tip 1/3Understated Self-view
Used when someone minimizes their own talents, abilities or accomplishments. 
He deprecatingly called himself an amateur, despite his expert play.
Pro Tip 2/3Humor or Modesty
Can indicate a sense of humor or an attempt to appear modest, not always serious self-criticism. 
Reacting to the applause, she deprecatingly joked that her piano piece was mere child's play.
Pro Tip 3/3Negative Emphasis
Places less value on one's contribution or role, often more than is accurate. 
During the meeting, he deprecatingly downplayed his role in the project's success.