sillily

adjective sillier, silliest

1. Obsolete
   1. simple; plain; innocent
   2. feeble; infirm; helpless
2. Now Rare feebleminded; imbecile
3. having or showing little sense, judgment, or sobriety; foolish, stupid, absurd, ludicrous, irrational, etc.: often used in a weakened sense to mean “unreasonably concerned”: don't be silly, it's no bother
4. frivolous or trivial
5. Informal dazed or senseless, as from a blow

noun pl. sillies