The term 'spur on' can be defined as to MOTIVATE or ENCOURAGE someone to do something. The crossword solutions for this term include PROD (4 letters), GOAD (4 letters), STIMULATE (9 letters), URGE (4 letters), INCITE (6 letters), ENCOURAGE (9 letters), EGG (3 letters), IMPEL (5 letters), INSPIRE (7 letters), ABET (4 letters), and MOTIVATE (8 letters). All of these words are related to the idea of motivating or encouraging someone to do something, either directly or indirectly. For example, PROD and GOAD are more direct forms of motivation, while STIMULATE and INSPIRE are more indirect forms of motivation. Similarly, URGE and IMPEL are more forceful forms of motivation, while ENCOURAGE and MOTIVATE are more gentle forms of motivation. Finally, INCITE and ABET are more subtle forms of motivation.