occasional vs part-time

occasional

adj
  • Acting in the indicated role from time to time. 

  • Created for a specific occasion. 

  • Occurring or appearing irregularly from time to time, but not often. 

  • Intended for use as the occasion requires. 

noun
  • A person who does something only occasionally. 

part-time

adj
  • For, during, or involving less than the normal time for some activity, especially the number of hours an employee works. 

How often have the words occasional and part-time occurred in a corpus of books? (source: Google Ngram Viewer )