Antonyms – Choose the word that is OPPOSITE in meaning to the highlighted word. Sentence: I was surprised at his stiff attitude. Target word: stiff (attitude)

Introduction / Context:
In interpersonal contexts, stiff attitude means rigid, unyielding, or inflexible behavior. The antonym therefore should capture willingness to bend, adapt, or accommodate. While polite or lively relate to manner or energy, they do not directly oppose rigidity.

Given Data / Assumptions:

• Target sense: stiff = inflexible in dealings.
• Part of speech: adjective modifying attitude.
• We must find the opposite trait.

Concept / Approach:
Antonym selection is sense specific. For attitudes, the primary dimension is flexibility versus rigidity. Therefore flexible directly reverses stiff in this usage.

Step-by-Step Solution:
1) Resolve intended sense: not physical stiffness, but social rigidity.2) Locate the antonym on the same dimension: flexible.3) Reject choices that change dimension to politeness or vigor.4) Confirm collocation: flexible attitude is idiomatic.

Verification / Alternative check:
Paraphrase: a stiff stance versus a flexible stance in negotiations. These form a natural opposition in business English.

Why Other Options Are Wrong:

• courteous: polite, not the opposite of rigid.
• soft: vague and not a standard antonym for rigid attitude.
• lively: energetic, unrelated to rigidity.

Common Pitfalls:
Choosing courteous because stiffness can feel impolite; however, the linguistic dimension being tested is rigidity, not manners.

Final Answer:
flexible