Here are some international words and terms that work well for an ambigram, focusing on positivity and brevity:

Short and powerful words:

• Hope – universal and positive
• Love – a classic, often used in ambigrams
• Joy – short, powerful, and cheerful
• Zen – minimalist and balanced
• Glow – radiates positivity and light
• Echo – repetition works well for an ambigram

Inspiring and positive concepts:

• Rise – related to motivation and growth
• Flow – ideal for dynamic design
• Shine – radiates energy and optimism
• Smile – universal and friendly
• Karma – spiritual and symmetrical
• Peace – related to harmony

Creative and playful options:

• Noon – already a natural ambigram!
• Wow / Mom – simple and playful reflection
• Ovo – symmetrical and minimalist
• Luz – (Spanish for “light”) internationally recognizable
• Yay – short and cheerful