What does it mean?
It is short for cuckservative.
Or, for a shorter treatment, you could look it up in the Urban Dictionary:
cuckservative
A name for weak-willed wusses that pretend to be "conservative". They are often found in the Republican party. A cuckservative is a cowardly pussy who sucks up to leftoid equalists for mercy and pisses himself when he gets accused of racism, sexism, or anti-semitism.Jeb Bush is a cuckservative
“cuckservative”
Also called a RINO.