Japa (or japam) means repeating or remembering a mantra (or mantram), and ajapa-japa (or ajapajapam) means constant awareness of the mantra, or of what it represents.
[citation needed] Thus, ajapa-japa is the practice of japa without the mental effort normally needed to repeat the mantra (effort is necessary for those who are not pure enough to dedicate themselves completely to God, and still have material desires, which is the cause of repeated reincarnation in samsara ocean).
In other words, it has begun to come naturally, turning into a constant awareness.
Says Swami Satchidananda: "You can perform japa, repetition of a mantra or Sacred Word, in the midst of your day-to-day work.
Then, when it becomes a habit, even when you are working intensely a portion of the mind will keep repeating the mantra always.