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