The term 'overfill' can be defined as having too much of something. This can be seen in the crossword solutions given, such as 'BLOAT' (5 letters), which means to become swollen or distended from being filled with too much air or fluid; 'STUFF' (5 letters), which means to fill something with an excessive amount of material; 'SATIATE' (7 letters), which means to satisfy fully; 'CROWD' (5 letters), which means to fill a place with an excessive number of people; 'GLUT' (4 letters), which means to supply with an excess of something; and 'SATE' (4 letters), which means to satisfy fully. All of these words refer to having too much of something, which is the definition of the term 'overfill'.