Poignant- adjective

Poignant means painfully affecting the feelings deeply affecting

Merriam- Webster’s dictionary

“Quicksand” by Nella Larsen

“Instinctively Helga was aware that their smiling submissiveness covered many poignant heartaches and perhaps much secret contempt for their instructors”

Now finding out the meaning of this word I now understand that they were showing pain in their face and smiling to cover it.