The term 'trouble afoot' can be summarized by the crossword solution 'BUNION, ' which is a medical condition caused by the enlargement of the joint at the base of the big toe. It is characterized by inflammation, pain, and tenderness in the area. BUNION can be caused by wearing tight or ill-fitting shoes, as well as by certain medical conditions such as arthritis. Treatment for BUNION includes wearing wider shoes, using orthotics, and taking anti-inflammatory medications. In severe cases, surgery may be necessary to correct the deformity.