Making the distinction between ''silly'' and ''stupid''
It's quite difficult to find the answer to this question in a dictionary due to the similarity of the two words, however there is a difference that should definitely be noted.
The word ''silly'' usually implies more carelessness, sometimes even just being frivolous. It can be offensive if not used carefully, but can also be a funny word and is generally is weaker than ''stupid''. Daft is very similar.
The word ''stupid'' is stronger, suggests more a lack of intelligence and is generally considered much more derogatory than the aforementioned word ''silly''.
In French, I know a few such words, like bête, stupide, idiote etc... however, I still don't know how to use words to make that same distinction as I can in English. I don't want to say something potentially very rude or make a bad overstatement, so I appreciate any help in advance.
'Bête' is close to 'silly'. For example: 'Don't be silly' = 'Ne sois pas bête'. You can say that to friends without offending them. Of course, 'stupide' and 'idiot' will be offensive, except in very rare cases. 'Kiss me, stupid' is 'Embrasse-moi, idiot' in French, but it is really old fashioned. We can say: 'Ne fais pas l'idiot' ('Do not pretend to be an idiot/Do not act like an idiot', in general when we mean to say: 'Do not do the stupid thing that you seem about to do') to a friend.
'Bête' can still be offensive, though. It is sometimes used to talk of real cretins. It is particularly offensive in its 'verlan' version, 'teubé'.