Learn Romanian: Am lăsat pantofii la cizmar. - I left the shoes at the cobbler.

The word for shoe is masculine: pantof. To make it plural (shoes), you add the first -i, making it pantofi. To add the word "the", you attach the definite article, which for masculine plural is another -i. Together, they form pantofii (the shoes).

Could I use the verb am plecat here for "I left" instead of am lăsat?

No, because they mean completely different things. You use a lăsa (here as am lăsat) when you leave an object behind or put something down. You use a pleca only when you yourself are departing or leaving a location.

In English it translates to "at the cobbler", so why isn't there a definite article on cizmar?

In Romanian, when a noun directly follows a simple preposition like la, în, or din, it usually drops the definite article. So you say la cizmar instead of la cizmarul, even though we translate it as "at the cobbler" in English.

If I wanted to say "I left the shoes at the new cobbler", would cizmar still drop the article?

No! If you add a descriptive word (an adjective) right after the noun, the preposition rule changes and you must bring back the definite article. You would say la cizmarul nou (at the new cobbler).