a term of contempt applied to a stupid, silly fellow ...1806 Eng. dial.
unknown; possibly from 'tim' + 'doodle', a simple fellow, a trifler
FIRST DOCUMENTED USE
? 1806 - See Example below
"...Shoar tha beestn'n sich a white liver'd saft-bak'd timdoodle,
As to think they'll titch ground this'm side of the poodle."
From: The Civil and Military History of Cornwall,
Literary Characters of Cornwall,
Cornish Dialogue Between Two Old Men
By the Reverend R. Polwhele, 1806
• The English Dialect Dictionary, Joseph Wright, 1898-1905
• A Dictionary of Archaic and Provincial Words, James Halliwell, 1855
• Glossary of Cornish Provincial Words, Fred W.P. Jago, 1882