Definitions:

1. a cognitive factor that tends to have an effect on what you do noun
   • My wishes had a great influence on my thinking.
2. a power to affect persons or events especially power based on prestige etc noun
   • They used their parents' influence to get the job.
3. have and exert influence or effect verb
   • The artist's work influenced the young painter
4. one having power to affect or change the opinion and viewpoint of another noun
   • My friends are the most important influence in my life.
5. the effect of one thing (or person) on another noun
   • the influence of mechanical action

Synonyms:

• act upon
• charm
• shape
• tempt