Slit adjectives are listed in this post. Each word below can often be found in front of the noun slit in the same sentence. This reference page can help answer the question what are some adjectives commonly used for describing SLIT.
deep, double, high, horizontal
inch, little, long, longitudinal
mere, narrow, open, single
small, thin, tiny, vertical
Hope this word list had the adjective used with slit you were looking for. Additional describing words / adjectives that describe / adjectives of various nouns can be found in the other pages on this website.