孤

adjective: alone, solitary, orphaned
孤

孤 is polysemous on Wiktionary (solitary/orphaned adjective, orphan noun, archaic imperial pronoun 'I', Hokkien-only adverb 'only'); picked the core 'solitary/alone' sense, which underlies compounds like 孤單, 孤獨, 孤立, 孤僻.