馬鹿げた

foolish: 〘ややかたく･主に書〙 で, 良識･判断力に欠けることをいう. 日常英語では代わりにsillyやstupidが用いられることが多い

stupid: 良識･思考力･判断力が欠如していることをいい, 人に用いると〘けなして〙 響く. 〘話〙 で好まれ, 〘書〙 では代わりに〘よりかたく〙 〘丁寧に〙 響くfoolishやunwiseなどが好まれる

silly: 分別･判断力･真剣さに欠け, 時に子供っぽく後に恥ずかしくなるような愚かさをいう. foolishやstupidほど語調は強くなく子供に対しては好まれるが, 大人に用いるとやはり〘けなして〙 響く

crazy: 〘くだけて〙 で, 良識･判断力に欠け奇異であることをいい, 通例〘けなして〙 用いる. 専門的に精神障害をさす場合はinsaneの方が普通

ridiculous: もっともな理由もなく, 嘲笑をさそうほどばかげていること

absurd: ridiculousとほぼ同じ意味で用いられるが〘よりかたく〙 で, 常識から外れて不合理なことを強調する. 〘米〙 より〘英〙 で好まれる

SIMPLE, FOOLISH, SILLY, FATUOUS, ASININE mean actually or apparently deficient in intelligence.

SIMPLE implies a degree of intelligence inadequate to cope with anything complex or involving mental effort.

e.g. considered people simple who had trouble with computers

FOOLISH implies the character of being or seeming unable to use judgment, discretion, or good sense.

e.g. foolish stunts

SILLY suggests failure to act as a rational being especially by ridiculous behavior.

e.g. the silly antics of revelers

FATUOUS implies foolishness, inanity, and disregard of reality.

e.g. fatuous conspiracy theories

ASININE suggests utter and contemptible failure to use normal rationality or perception.

e.g. an asinine plot

source: [【プラスチック姉さん】ひたすら友人をからかい悪ふざけする姉さんのGIF画像｜無料GIF画像検索 GIFMAGAZINE 855007]

adjective (sillier, silliest)

having or showing a lack of common sense or judgment; absurd and foolish:

〈人が〉愚かな, ばかな, 賢明さのない; 〖it is ～ of A/A is ～ to do〗 (人を評価して)…するなんてA〈人〉はばかである

e.g. another of his silly jokes

e.g. “Don't be silly!” she said.

ridiculously trivial or frivolous:

〈物･事が〉くだらない, ふざけた, ばかばかしい, (後で考えると)恥ずかしい; ｟主に英｠ 〈価格が〉あきれるほど低い

e.g. he would brood about silly things.

as complement used to convey that an activity or process has been engaged in to such a degree that someone is no longer capable of thinking or acting sensibly:

｟話｠ 気絶して, 気が遠くなって, 目を回して

e.g. he often drank himself silly

e.g. his mother worried herself silly over him.

archaic (especially of a woman, child, or animal) helpless; defenseless.

noun (plural sillies) informal

a foolish person (often used as a form of address):

｟話｠ まぬけ, ばか

e.g. come on, silly.

high summer regarded as the season when newspapers often publish trivial material because of a lack of important news.

sillily | ˈsiləlē | adverb

late Middle English (in the sense ‘deserving of pity or sympathy’): alteration of dialect seely ‘happy’, later ‘innocent, feeble’, from a West Germanic base meaning ‘luck, happiness’. The sense ‘foolish’ developed via the stages ‘feeble’ and ‘unsophisticated, ignorant’.