Adding -ful or -fully
The suffix -ful can form nouns or adjectives, like plateful or cheerful. People sometimes make the mistake of spelling this type of word with a double l at the end. Note that it’s always spelled with just one -l:
Examples: dreadful, faithful, skilful, powerful
The related ending –fully forms adverbs. Remember that this suffix is always spelled with two l’s:
Examples: dreadfully, faithfully, skilfully, powerfully
