1. By fits.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• forfully,
• fightfully,
• dutfully,
• faitfully,
• faihfully,
• pitfully,
• fitfull,
• fathfully,
• fistfull,
• faitfuly,
• faitfull,
• duitfully,
• fiffully,
• fiftfully,
• fittfully,
• fitfuly,
• fitfulli,
• fienfully,
• rithfully,
• Witfulle

• fitfulness,
• fitful.

The adjective form of the word "fitfully" is "fitful".

The plural form of "fitfully" is "fitfully". The word does not change in plural form, as it is an adverb and does not refer to a specific countable noun.

The singular form of the word "fitfully" is "fitful"