The term 'strongly attractive' can be summarized by the crossword solution 'MAGNETIC'. MAGNETIC refers to the force of attraction between two objects that have a MAGNETIC field. This force is created by the motion of electrons and can be used to attract or repel other objects. MAGNETIC forces are strongest when the two objects have opposite poles, such as north and south. MAGNETIC forces are also used in many everyday applications, such as in motors, generators, and compasses.