* Pagkakaugnay ng mga pandama (literally "connection of the senses")
* Pagsasama ng mga pandama (literally "combination of the senses")
* Panghihinuha ng pandama (literally "sensory inference")
You could also use a more specific phrase depending on the type of synesthesia, for example:
* Grafema-kulay na synesthesia (grapheme-color synesthesia)
* Tunog-kulay na synesthesia (sound-color synesthesia)
It's important to note that these are not literal translations but rather explanations of the concept using Tagalog words and phrases.