Antonyms of adj sudden

1 sense of sudden

Sense 1
sudden (vs. gradual) -- (happening without warning or in a short space of time; "a sudden storm"; "a sudden decision"; "a sudden cure")

gradual (vs. sudden) -- (proceeding in small stages; "a gradual increase in prices")
        => bit-by-bit, in small stages, piecemeal, step-by-step, stepwise -- (one thing at a time)
        => gradational, gradatory, graduated -- (taking place by degrees)

Similarity of adj sudden

1 sense of sudden

Sense 1
sudden (vs. gradual) -- (happening without warning or in a short space of time; "a sudden storm"; "a sudden decision"; "a sudden cure")
       => abrupt -- (exceedingly sudden and unexpected; "came to an abrupt stop"; "an abrupt change in the weather")
       => choppy, jerky -- (marked by abrupt transitions; "choppy prose")
       => emergent -- (occurring unexpectedly and requiring urgent action; "emergent repair of an aorta")
       => explosive -- (sudden and loud; "an explosive laugh")
       => fulminant -- (sudden and severe; "fulminant pain"; "fulminant fever")
       => sharp -- (very sudden and in great amount or degree; "a sharp drop in the stock market")
          Also See-> fast#1