Long adjectives are compared by means of more and most:
Positive | Comparative | Superlative |
crowded | more crowded | the most crowded |
confused | more confused | the most confused |
charming | more charming | the most charming |
expensive | more expensive | the most expensive |
convenient | more convenient | the most convenient |
delightful | more delightful | the most delightful |
frightened | more frightened | the most frightened |
convenient | more convenient | the most convenient |
beautiful | more beautiful | the most beautiful |

Comparison with more and most
The following long adjectives may also be compared by adding -(e)r and -(e)st, of by means of more and most.
Positive | Comparative | Superlative |
handsome | handsomer more handsome |
the most handsome |
profound | profounder more profound |
the most profound |
severe | severer more severe |
the most severe |
pleasant | pleasanter more pleasant |
the most pleasant |
common | commoner more common |
the most common |
sincere | sincerer more sincere |
the most sincere |
precise | preciser more precise |
the most precise |
concise | conciser more concise |
the most concise |
Note:
Unlike the construction the definite article + superlative, the construction the indefinite article + superlative is not used for comparison, but to denote a high degree of some quality.