怪(あや)しい

彼(かれ)の英語(えいご)は怪(あや)しい。ネイティブではないだろう。

His English is dodgy. He's probably not a native speaker. {suspicious, dubious, doubtful, dodgy, suspicious (referring to a potential amorous relation), dangerous (e.g. financial situation), ominous (e.g. weather), strange, shady, fishy, charming, bewitching, mysterious}

雲行(くもゆ)きが怪(あや)しいです。もうすぐで雨(あめ)が降(ふ)りそうです。

The clouds look ominous. It seems like it's going to rain soon. {suspicious, dubious, doubtful, dodgy, suspicious (referring to a potential amorous relation), dangerous (e.g. financial situation), ominous (e.g. weather), strange, shady, fishy, charming, bewitching, mysterious}

母親(ははおや)が子供(こども)に：「怪(あや)しい人(ひと)には近(ちか)づかないでね。危険(きけん)だから。」

A mother says to her child: 'Don't go near suspicious people. It's dangerous.' {suspicious, dubious, doubtful, dodgy, suspicious (referring to a potential amorous relation), dangerous (e.g. financial situation), ominous (e.g. weather), strange, shady, fishy, charming, bewitching, mysterious}

監督(かんとく)：「このままだと次(つぎ)の試合(しあい)の勝利(しょうり)は怪(あや)しいので、休憩(きゅうけい)抜(ぬ)きで練習(れんしゅう)しましょう。」

Coach: 'If things stay as they are, our victory in the next game is doubtful, so let's practice without taking a break.' {suspicious, dubious, doubtful, dodgy, suspicious (referring to a potential amorous relation), dangerous (e.g. financial situation), ominous (e.g. weather), strange, shady, fishy, charming, bewitching, mysterious}

兄(あに)はバイト先(さき)の同僚(どうりょう)と怪(あや)しい。もしかすると、とっくに付(つ)き合(あ)っているかもしれない。

My brother is suspicious with his part-time job colleague. They might have been dating for a while. {suspicious, dubious, doubtful, dodgy, suspicious (referring to a potential amorous relation), dangerous (e.g. financial situation), ominous (e.g. weather), strange, shady, fishy, charming, bewitching, mysterious}