状態・変化N2
〜っぱなし
leave... as is / keep... without attending to it
Structure
V-ます形（語幹）+ っぱなし
Explanation
Indicates leaving a state unattended and unchanged, often with dissatisfaction or blame. Attached to the masu-stem of verbs (テレビをつけっぱなし, 言いっぱなし). Also used as 〜っぱなしのN.
Examples
電気をつけっぱなしで、寝てしまった。
I fell asleep leaving the light on.
借りた本を読みっぱなしにして、返すのを忘れた。
I left the borrowed book half-read and forgot to return it.
Note
っぱなし is usually negative and critical. Similar to まま, but stresses an unfinished, neglected state.