The word "不屈不挠" is formed by combining two parallel phrases, each starting with the negation "不" (meaning "not") followed by verbs with similar meanings: "屈" (meaning to bend or submit) and "挠" (meaning to bend or yield). This juxtaposition creates a four-character compound where the repeated structure emphasizes a complete refusal to submit, literally translating to "not bend, not yield" to convey unyielding perseverance.