3 Old HSK word(s): ☊孤立 ** C ☊孤单 ** D ☊孤独 ** D
孤* * 托孤* * 遗孤* *

Definitions from Unihan Copyright © 1991-2015 Unicode® Inc. All rights reserved.

遗 lose / articles lost / omit
孤 orphan, fatherless / solitary

Hsk Characters: 孤 *
HSK -Characters and beyond:
GbBig5EngRadMegaTripleMultilingual
孤 5B64 + 孤 + + orphan, fatherless / solitary 子 瓜 Child 瓜 (2KÜRBIS) gu1 +

Korean:

孤 + 孤 외로울 고 (외로우다: lonely) or 부모 없을 고 (without any parents, i.e. an orphan)
3 NHSK word(s): 孤单* 4 gu1 dan1lone/ lonely/ loneliness 孤独* 6 gu1 du2lonely/ solitary 孤立* 6 gu1 li4isolate/ isolated
KOREAN6000 word(s):
0 KOREAN 2500 New HSK words):
0 KOREAN Sentence(s):