The term 'held fast' can be described by the crossword solutions of 'STUCK, ' 'ADHERED, ' 'CLUNG, ' 'clasped, ' and 'GRASPED.' All of these words imply a strong, secure grip on something. 'STUCK' implies that something is unable to move, while 'ADHERED' suggests that something is attached to another object. 'CLUNG' and 'clasped' both suggest a tight grip, and 'GRASPED' implies a firm understanding of something. All of these words together suggest that something is held firmly in place.