• Basic forms
• 驚く — be surprised / base form
• 驚きます — is surprised / masu form
• 驚いた — was surprised / ta form
• 驚いて — being surprised … / te form
• 驚かない — am not surprised / negative
• 驚けば — if (one) is surprised / conditional
• Common expressions
• 知らせに驚く — be surprised by the news
• 音に驚く — be startled by a sound
• 驚くほど — to an astonishing degree
• More
• 驚いている — is surprised / state

驚く（おどろく） is a godan intransitive verb. It describes the feeling of surprise caused by something unexpected.

• Basic forms
• 驚かす — surprise; startle / base form
• 驚かします — surprises; startles / masu form
• 驚かした — surprised; startled / ta form
• 驚かして — surprising … / te form
• 驚かさない — do not surprise / negative
• 驚かせば — if (one) surprises / conditional
• Common expressions
• 人を驚かす — surprise someone
• 突然驚かす — startle suddenly
• みんなを驚かす — amaze everyone
• More
• 驚かせないで — don’t scare me / request

驚かす（おどろかす） is a godan transitive verb. It means to cause surprise or shock in someone else.