A variant or humorous spelling possibly related to doolie or other dool- words, though it's not a standard dictionary entry.
Possibly a dialectal variant or playful alteration, though this form lacks clear etymological documentation in major English sources.
Some words fade from use or exist only in regional speech, making them hard to document—'doolfu' might be a genuine dialectal variant that survives in spoken English but rarely appears in writing.
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