often (frequently, many times): I often go for a walk after lunch.
a lot informal (frequently, many times): I see him in the park a lot.
frequently formal (often): We update the systems frequently.
again and again (many times): She mopped the floor again and again.
repeatedly (many times): I repeatedly told him to lock the door.
time and again (many times; very often): I’ve told you time and again not to come late!
constantly (very often; all the time): She was constantly changing her mind.