Definition of thinko in English:

thinko

noun

informal
  • A mistake in one's thought processes; a mental lapse or failure to reason correctly.

    • ‘The problem, I began to suspect, was not a typo but a thinko.’

Origin

1990s: formed on the pattern of typo.

Pronunciation:

thinko

/ˈθɪŋkəʊ/