Somewhat faint; slightly faint, weak, or timid; having a quality of faintness.
From 'faint' plus the suffix '-ish' (somewhat, rather, having the quality of). The '-ish' suffix allows for gradations and approximations in English.
The '-ish' suffix is incredibly productive in English because it lets you express 'sort of' or 'kind of'—so 'faintish' means you're not quite faint enough to describe as faint, a useful distinction for subtle gradations.
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