Most adjectives follow the noun they describe, but the following adjectives drop the final -o if placed before a masculine noun in the singular:

bueno - good; malo - bad; alguno - some; ninguno - no, any; uno - one; primero - first; tercero - third

When grande means great, it precedes the noun and drops the -de before a singular noun of either gender.  Santo (saint) drops the -to before all masculine nouns, except those beginning with Do- or To-.

To Say and to Go Out