'Sweet' could mean any thing sweet - from not very sweet to very, overly sweet. 'Sweetish' means just a little sweet, but not much. 'This ice cream is very sweet." "This fruit is somewhat sweetish - not too much, but I can definitely taste it." There is also slang - If a boy likes a girl romantically, but hasn't really gotten serious, we say "He is sweet on her." It can work the other way - a girl can be sweet on a guy. "Sweetish" could be used in this case, but I almost never hear it.

ok,i see, thank u ,

"Sweetish" 不是一个真正的英文次。 "-ish" 是一个非正式形容词的后缀，附在形容词上，形容词的意思变成"小一点"， 所以sweetish的意思是a little bit sweet.