Nouns ending in a consonant followed by -y change the -y to -ies in the plural form.
Heavily is regular. It follows the -ies Conversion rule.
Use plural verbs: "The heavilies are ready" (not "is ready").
Yes. The plural heavilies is standard across all English variants.
The word heavily follows the standard English pluralization rule. When forming the plural, heavily becomes heavilies. This follows the -ies Conversion pattern, which is one of the most common plural rules in English.
Understanding why heavily becomes heavilies helps with spelling and pronunciation. Nouns ending in a consonant followed by -y change the -y to -ies in the plural form.
When using heavilies in writing, remember that it functions as a plural noun in sentences. It pairs with plural verbs and pronouns. For example: "The heavilies are ready" (not "is ready"). This subject-verb agreement is essential for grammatical correctness.