full-time vs occasional

full-time

adj
  • Involving a full amount of time spent on some activity, especially a job. 

adv
  • Spending a full amount of time. 

occasional

adj
  • Created for a specific occasion. 

  • Acting in the indicated role from time to time. 

  • 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. 

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