We often make an adverb by adding -ly to an adjective, for example: quick > quickly.

Spelling Rule
Just add -ly to the end of the adjective:

coy > coyly
loud > loudly
beautiful > beautifully
senseless > senselessly
intelligent > intelligently
Exceptions

If the adjective ends in:
do this:
and add:
For example:

-ll
nothing
-y
full > fully

consonant + -le
remove the final -e
-y
terrible > terribly

-y (except 1-syllable adjectives)
remove the -y
-ily
happy > happily

Note: 1-syllable adjectives ending in -y are regular, except:
day > daily
gay > gaily