quel joli (masc.) / quelle jolie (fem.) means 'what a pretty ...noun)' in French.
The word 'quel' is an interrogative pronoun. It's in the masculine singular form. The plural form is 'quels'. The feminine singular and plural forms are 'quelle', and 'quelles', respectively. But...
It can mean - which man? or what a man!
Un chapeau (masc.) is 'a hat' in English.
What age are you