Definition from Wiktionary, the free dictionary
mainly (not comparable)
- (obsolete) Forcefully, vigorously. [14th-17th c.]
- (obsolete) Of the production of a sound: loudly, powerfully. [14th-19th c.]
- But in the end, mainly crying out, he fell to raling and wringing his master, upbraiding him that he was not a true Philosopher […].
- (obsolete) To a great degree; very much. [15th-19th c.]
- Chiefly; for the most part. [from 17th c.]
1913, Joseph C. Lincoln, chapter 12, in Mr. Pratt's Patients:
- She had Lord James' collar in one big fist and she pounded the table with the other and talked a blue streak. Nobody could make out plain what she said, for she was mainly jabbering Swede lingo, but there was English enough, of a kind, to give us some idee.
chiefly; for the most part