To make something fashionable or to adapt something according to current fashion standards.
From 'fashion' plus the suffix '-ize' (to make or cause to become), following the pattern of words like 'modernize' and 'sanitize'. This is a relatively rare verb that never became standard.
While most people say 'make fashionable,' the suffix '-ize' is incredibly productive in English—it lets us turn almost any noun into a verb meaning 'to make or cause to become' that thing.
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