silly

1 silly /ˈsɪli/ adjective
sillier; silliest
1 silly
/ˈsɪli/
adjective
sillier; silliest
Britannica Dictionary definition of SILLY
[also more silly; most silly]
1 
: having or showing a lack of thought, understanding, or good judgment : foolish or stupid
2 
: not practical or sensible
3 
a  : not serious, meaningful, or important
b  : playful and funny
4 
not used before a noun : in a condition in which you are unable to think clearly

— silliness

/ˈsɪlinəs/ noun [noncount]
2 silly /ˈsɪli/ adverb
2 silly
/ˈsɪli/
adverb
Britannica Dictionary definition of SILLY
informal
: to an extreme degree
3 silly /ˈsɪli/ noun
3 silly
/ˈsɪli/
noun
Britannica Dictionary definition of SILLY
[noncount] informal
— used to address someone who is being silly