Qual é a diferença entre 一人ぼっち e 一人きり e 寂しい e 孤独 ?Podes indicar apenas respostas exemplo.

ぼっち is from 法師（ほうし= a priest.）
In old days, a priest who is not belonging to any religious faction is called "独り法師(an alone priest.)"
So, ひとりぼっち means alone guy who has no friend nor companion.
ひとりぼっち has a image of child saying because that word always used in old tales for children.
You can use it on any situation but, in formal place or on buiness, using 一人きり is better I think.


一人きり just means "only 1 person."

寂しい means "lonely." regardless of which you are alone or not.(But alone makes you 寂しい, you know.)


孤独 means "solitude, solitary." Using only Kanji no Hiragana nor Katakana, it has a image of a little bit serious situation.



good luck :)