What Does Write-Only Language Mean?
A write-only language is a humorous term for a language in which only the coder can comprehend the code that he/she has written in that language. This can be due to a number of reasons, some of which include the complexity of syntax and the flexibility of the piece of code.
Techopedia Explains Write-Only Language
Very basic types of write-only languages include TECO and INTERCAL (both of which are considered obsolete languages now). JavaScript and Perl can be regarded as write-only because the code written can often be unintelligible to a fairly experienced observer (but the coder can easily understand his/her own code). JS and Perl are not always indecipherable but a well-written, well-maintained and commented piece of code can be comprehensible to a common viewer. C and C++ are sometimes said to be write-only because it is easier to write code in them than to understand what has been written.