merry > amusing, delightful, charming fit > mood, humour rear > {Bring into existence; resume}
3 And did of joy and jollity devise,
jollity > pleasure; lust devise > talk
4 Herself to cherish, and her guest to cheer:
cherish > entertain; cheer
5 The knight was courteous, and did not forbear 6 Her honest mirth and pleasance to partake;
pleasance > pleasing behaviour partake > share, share in
7 But when he saw her toy, and gibe, and jeer, 8 And pass the bounds of modest merrimake,
merrimake > merry-making
9 Her dalliance he despised, and follies did forsake.