IPA: /ˈdʌstɪli/
KK: /ˈdʌstɪli/
In a manner that is covered with dust or resembles dust.
The old book sat dustily on the shelf, untouched for years.
Dustily → It is formed from "dust" (from Old English *dust*, meaning fine particles of earth or powder) and "-ily" (a suffix forming adverbs, meaning in a manner). The word "dustily" means in a manner that is covered with or resembles dust.
Think of fine particles of earth ('dust') and how something can be done 'in a manner' ('-ily') that resembles being covered in dust.