largely vs lengthily

largely

adv
  • In a widespread or large manner. 

  • For the most part; mainly or chiefly. 

  • On a large scale; amply. 

lengthily

adv
  • In a lengthy way, in a manner that is long and drawn out, especially in time. 

How often have the words largely and lengthily occurred in a corpus of books? (source: Google Ngram Viewer )