When combined, the structure `看 + 不 + 懂` (Verb + Negative Potential + Result) means that the action of looking (看) is performed, but the result of understanding (懂) is not achieved.
While 看不懂 (kànbudǒng) isn't a term loaded with deep philosophical meaning like 关系 (guānxi), its structure reveals something fundamental about the Chinese language: efficiency and precision. In English, “I don't understand” is a general statement. We need to add context to be more specific: “I don't understand what I'm reading,” or “I don't understand this movie.” Chinese, however, builds the context directly into the verb phrase. 看不懂 (kànbudǒng) specifically tells the listener that the failure to understand comes from a visual source. Its counterpart, 听不懂 (tīngbudǒng), specifies that the failure comes from an auditory source. This “Verb-Result” structure is a core pillar of Chinese grammar. Grasping it early on is a huge step for learners. For a culture that often values clarity and directness in expressing practical matters, being able to precisely state how you are failing to understand is highly efficient and useful. It's a humble and clear way to ask for help or clarification without ambiguity.
看不懂 is an extremely common, everyday phrase used in both formal and informal situations. Its connotation is neutral; it's simply a statement of fact.