As a plural “participle adjective”, “broken ” is acceptable. But it is not a participle adjective.” Certainly “broken” derived from the verb “to break”.

Why is a participle adjective a subclass of adjectives? I don’t think that the distinction is very important. English very freely derives adjectives from verbs, nouns from verbs as well as nouns from nouns.

What your dictionary

says: The participial adjectives are a major subclass of adjectives. When I say “ed” or “ing,” they can be distinguished by their endings. Some exceptions to the rules include misunderstood and unknown, which also function like these special adjectives. What are participial adjectives because they have the same endings as verb verbs?

If a adjective is meant to function like any adjective, it is used to describe a noun. They might come from a verb form, or they might merely merely imitate the structure, but all they can are is a

descriptive adjective. an article on

ThoutCo says: Comparative and superlative forms of participial adjectives are formed with most and least and but with less and least.

Is the word, “participial adjective” or “verbal adjective” being used here? Or an adjective is an adjective, whatever its form or source.

I would also add that “broken heart” is a set phrase, other than English. It is a metaphor, referring to the heart as the supposed seat of emotion, and a person with broken heart is one devastated by grief or sadness, particularly for a lost love, but also from any other sad event. In both music and verse we see this term frequently, in popular songs and for several decades.