True-blue

a.	1.	Of inflexible honesty and fidelity; - a term derived from the true, or Coventry, blue, formerly celebrated for its unchanging color. See True blue, under Blue.
n.	1.	A person of inflexible integrity or fidelity.

Adj.

1.

true-blue - marked by unswerving loyalty; "a true-blue American"; "a reliable true-blue country club conservative"

loyal