* Ancianito: This is a common and generally affectionate term. It emphasizes the "little" and "old" aspects.
* Viejecito: Similar to ancianito, this also emphasizes both age and small size, but can sometimes sound slightly more informal or even playful.
* Abuelito: This means "little grandfather" and is very affectionate, implying a kindly old man. It's not suitable if you're not talking about someone who is a grandfather figure.
* Hombrecito viejo: This is a more literal translation, meaning "little old man." It's grammatically correct but might sound a bit stiff or less affectionate than the other options.
The best choice will depend on the context. If you can provide more context, I can help you choose the most appropriate translation.