Meanings
- To not know anything about something.
For all her experience, she didn't have the first idea what it was like to have the disease.
2005, Simon Riley, Beating Cancer. A Miracle on the NHS, →ISBN, page 1892 more examples
Reading them was another; and when it came to taking thoughts in his head and writing them on to paper, he didn't have the first idea where to start.
2010, Stephen Deas, The Thief-Taker's Apprentice, →ISBNThe decision had been made, and the world had now been advised. The Super would be built. But the scientists at Los Alamos didn't really have the first idea how to do it.
2011, Jim Baggott, The First War of Physics, →ISBNSynonyms: not know the first thing, not have the faintest idea
Synonyms & antonyms
verbTo not know anything about something.
Cite this entry
not have the first idea. (n.d.). In WatkinsX Dictionary. Retrieved November 5, 2026, from https://dictionary.watkinsx.com/word/not%20have%20the%20first%20idea
“not have the first idea.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/not%20have%20the%20first%20idea. Accessed November 5, 2026.
WatkinsX Dictionary, s.v. “not have the first idea,” accessed November 5, 2026, https://dictionary.watkinsx.com/word/not%20have%20the%20first%20idea.
Source: not have the first idea on Wiktionary, CC BY-SA 4.0.