frequent vs shop at

frequent is an adjective but shop at is not an adjective.

Word	Noun	Adjective	Verb	Adverb
frequent	No	Yes	Yes	No
shop at	No	No	Yes	No

As verbs, frequent and shop at are synonyms defined as:

frequent and shop at: do one's shopping at; do business with; be a customer or client of

Other synonyms of frequent include buy at, patronise, patronize, shop, sponsor.

frequent (adjective)	shop at (adjective)
coming at short intervals or habitually
frequently encountered

frequent (verb)	shop at (verb)
be a regular or frequent visitor to a certain place	do one's shopping at; do business with; be a customer or client of
do one's shopping at; do business with; be a customer or client of