"against" as a preposition indicating opposition

"खिलाफ"

English Usage: "He stood against the proposal."

Hindi Usage: "वह प्रस्ताव के खिलाफ खड़ा हुआ।"

"ion" as an electrically charged atom or molecule

"आयन"

English Usage: "The solution contains positive and negative ions."

Hindi Usage: "घोल में सकारात्मक और नकारात्मक आयन होते हैं।"