ぱなし ( panashi) comes from the verb 放す (hanasu) meaning to let something go. An example such as 出しっぱなし = 出しっ放し (dashippanashi) means to leave something as it was taken out. For example i left the garbage as it was when I left it out.
Since the verb in front of はなし (hanashi) should end with small っ (tsu), we pronounce ぱ ( = pa) instead of は ( = ha) the adding of ぱなし ( = panashi) to a verb, you can describe something that has been left in a certain condition for some time.
Panashi is usually used for somethign that is unintentionally done unless you say わざと/敢えて(on purpose)〜っぱなしにしておく。 ( = Wazato / Aete ~ ppanashi ni shiteoku.) Leave them —– on purpose
We can consider a situation where Yuka took off her coat and left it on the floor. Here the verb “to take off” is 脱ぐ ( nugu) and the ます ( masu) form is 脱ぎます. Here the ます (masu) form is removed and っぱなし ( = ppanashi) is added.
So in what situations can we use this ?
here i will describe some example situations for use:
あの人はなんでもやりっぱなしだ。
= Anohito wa nandemo yarippanashi da.
He always leaves things unfinished.
•彼はずっとしゃべりっぱなしだ。
= Kare wa zutto shaberippanashi da.
= He just keeps talking without stopping.
Some daily language usage for ~ppanashi~
•出しっぱなし = だしっぱなし ( = dashippanashi) to leave (water) running
• 差しっぱなし =さしっぱなし ( = sashipanashi) to leave something plugged in
•あけっぱなし = 開けっぱなし = ( = akeppanashi) to leave something open
•流しっぱなし =ながしっぱなし ( = nagashippanashi) to leave the water running
•かけっぱなし ( = kakeppanashi) to leave it turned on
• 付けっぱなし = つけっぱなし ( = tsukeppanashi) to leave the light on