っぱなし

1. 1Leaving something in the state that resulted from an action, without tidying it up or undoing it.Ex. 1
2. 2Keeping on doing something, or staying in a state, continuously for a long time.Ex. 2

Common in everyday conversation and casual writing, often to criticize or complain about something left unattended, such as lights on, doors open or water running, or an activity that goes on too long. In the continuing sense it can also be neutral or sympathetic, as in 頑張りっぱなし for someone who keeps working hard. Unlike まま, which neutrally describes an unchanged state, っぱなし usually adds a sense of negligence or excess.

• ままN4「まま」 objectively expresses that a state remains unchanged, is stylistically neutral, and can attach to verbs, adjectives, or nouns, while 「っぱなし」 attaches only to verbs. For cases like leaving a light on or a door open you can substitute 「〜たまま」, but the critical tone disappears; 「言いっぱなし」 cannot be swapped.
• 〜たきりN3「たきり」 attaches to the ta-form of a verb, is stylistically neutral, and stresses that after doing something the expected follow-up never happened (the following clause is often negative); 「っぱなし」 centers on something that should be dealt with being left unattended, or an action continuing nonstop, usually with a critical tone, so the two are generally not interchangeable.
• 続けるN4「続ける」 is close only to the 'continuing for a long time' sense of 「っぱなし」, but it is stylistically neutral and can also express deliberately keeping something up. The sense of doing something and then not cleaning up or dealing with it afterward can only be expressed with 「っぱなし」.
• てしまう / ちゃうN4「てしまう」 means completing something or that it is beyond recovery, while 「っぱなし」 means leaving something unattended after doing it, or a state continuing; the former attaches to the te-form, the latter to the masu-stem (the ます form with ます removed). They are not interchangeable but can be used together: 「つけっぱなしで寝てしまった」.
• がちN3「がち」 indicates that bad situations easily happen and recur, focusing on tendency and frequency; 「っぱなし」 refers to a post-action state being left unattended or continuing without interruption. 「がち」 can also attach to nouns and is stylistically neutral, so the two cannot be interchanged.

まま neutrally describes an unchanged state, while っぱなし suggests neglect or excess, and 〜たきり stresses that nothing followed an action. 続ける marks neutral, often intentional continuation; てしまう expresses completion or regret rather than a lingering state; and がち describes a tendency to happen often rather than one unbroken state.