How to use “boast of” or “boast about” (not “boast for”)

❌ Don’t say this: James boasted for his strength (talked with too much pride about something you have or can do).

✅ Say this: James boasted of his strength.

✅ Or say this: James boasted about his strength.

Why “for” is wrong and “of” or “about” are correct

The word boasted means “talked with too much pride about something you have or can do.” In English, you boast of or boast about something — never boast for. Think of of as pointing to the thing you own (proud of) and about as talking around a topic (talk about, brag about). The preposition for is wrong here because for shows purpose or benefit (pay for, wait for, famous for) — not the thing you are bragging about.