good at sth
fixed phr..fixed phr.. Describes someone who has the skill or ability to do something well.
fixed phr.. An adjectival phrase, `good at + noun/gerund`, used to express proficiency in a particular domain.
He is good at math.
She's always been good at remembering names, which is a useful skill for a manager.
While not naturally good at public speaking, the senator honed her skills through years of practice and became a formidable orator.
Followed by a noun (like a subject or activity) or a gerund (-ing form of a verb).
Contrast 'good at' (for skills/activities) with 'good with' (for handling people/tools) and 'good for' (for health/benefit).
I am good in playing tennis.I am good at playing tennis.The correct preposition to follow 'good' for skills and activities is 'at', not 'in'.