adverb
without fail; diligently; without missing a single ...
Used to describe doing something consistently, every time, or without skipping any instance. Often followed by a verb in the negative form or a positive habitual action.
See also: 欠かす (かかす)
彼は毎朝欠かさずジョギングをしている。
He goes jogging every morning without fail.
祖母は毎日欠かさず日記をつけている。
My grandmother keeps a diary every day without missing a single day.