Mighty in Chinese / Japanese...

強大 can mean mighty, powerful, large, formidable, or strong.

This term is often used to describe soldiers/troops/warriors, and whole armies.

気の強い means strong-willed or strong of heart in Japanese.

Here's the character breakdown of this Japanese title:
気 (ki) spirit; mind; heart; nature; motivation; intention; feelings; essence.
の (no) possessive particle.
強い (tsuyoi) strong; powerful; mighty; potent; resistant; resilient; durable.

Note: Because this selection contains some special Japanese Hiragana characters, it should be written by a Japanese calligrapher.

This literally means "strong man" but is more commonly used as a title for sumo wrestlers.

In Japanese, this is a Rikishi.

力士 is also used in Chinese and old Korean with the same meaning. Occasionally, this will also be used to refer to a strong or mighty man, hero, demigod etc. But anyone in the CJK world will first think of a sumo wrestler before the more literary usage as a strong man or demigod.

傲世 is a word used to describe someone that is very proud, and holds themselves above others but with a valid (earned) reason to do so. 傲世 is what you would use to describe the way a mighty general of ancient China like Cao Cao acted or a more modern person like General Patton carried himself.

If you hang this word on your wall it suggests that you hope to achieve that same level of pride from accomplishment.

最偉大的愛 means "the greatest love," in Chinese.

Keeping in mind that Chinese is different than English, the first character is like "-est" or adding "the most" as a modifier to the next word.
The 2nd and 3rd characters are a word meaning great, mighty, and/or large.
The 4th is a possessive article.
The last is the character for love.

When you put it all together, you get a phrase that means, the greatest love, the biggest love, or the mightiest love.

強い体強い心 is a way to write "strong mind, strong body" in Japanese.

Each of the two lines starts with 強い (tsuyoi) which means: strong; powerful; mighty; potent; resistant; resilient; durable; tough; stiff; hard; inflexible.

Body is represented with 体 (ancient version is 體, romanized as karada) which means: body; build; physique; posture; torso; trunk; health.

Mind is represented with 心 (kokoro) which can mean heart, mind, or soul depending on context.

This is not a common phrase in Japanese, so it's not the most natural title for calligraphy. In English, you might want to write it, "strong mind, strong body" but, "strong mind, strong body," is more natural in Japanese.

Note: Because this selection contains some special Japanese Hiragana characters, it should be written by a Japanese calligrapher.