The word TOPS may be used as an adjective or adverb. As the former it means highest in quality, ability, popularity, or importance. As the latter it means at the very most:
He’s a real expert, tops in his field.
I can’t lend you that much money. Fifty bucks, tops.
If you go by train, it’ll take you ten minutes tops to get to the airport.
Can I stay at your place? Just for a couple days, a week, tops.
She was tops in her class, but some kids didn’t like her very much.
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