compiler vs C compiler

compiler and C compiler both are nouns.

Word	Noun	Adjective	Verb	Adverb
compiler	Yes	No	No	No
C compiler	Yes	No	No	No

As nouns, C compiler is a hyponym of compiler; that is, C compiler is a word with a more specific, narrower meaning than compiler:

compiler: (computer science) a program that decodes instructions written in a higher order language and produces an assembly language program
C compiler: a compiler for programs written in C

Other hyponyms of compiler include Fortran compiler, LISP compiler, Pascal compiler.

compiler (noun)	C compiler (noun)
(computer science) a program that decodes instructions written in a higher order language and produces an assembly language program	a compiler for programs written in C
a person who compiles information (as for reference purposes)