In the following question, choose the option that is opposite in meaning to the given word: Vexatious.

Introduction / Context:
This question asks for an antonym of the word vexatious. Antonyms test whether a learner not only knows the meaning of a word but can also recognise its opposite. Vexatious is a descriptive term used for things that cause annoyance, worry or irritation. Understanding both the word and its opposite helps improve expressive range in English, especially for descriptive writing and comprehension passages.

Given Data / Assumptions:
- Target word: Vexatious.
- Options: Calamitous, Treachery, Soothing, Pliable.
- We must select the option which means the opposite of vexatious.
- The context is standard English vocabulary, not a special technical field.

Concept / Approach:
Vexatious describes something that causes a lot of trouble, annoyance or worry. For example, a vexatious problem or a vexatious delay disturbs or irritates those who face it. The opposite of causing irritation would be something that calms, comforts or relaxes. Among the options, Soothing clearly carries this sense of comfort and relief. Calamitous means causing great damage or disaster, Treachery means betrayal, and Pliable means easily bent or influenced, none of which represent the calming opposite of vexatious.

Step-by-Step Solution:
Step 1: Recall that vexatious means extremely annoying or causing persistent trouble.Step 2: Consider Calamitous. This means disastrous or causing a major calamity, which is more serious than mere annoyance and not the exact opposite.Step 3: Treachery refers to betrayal of trust and does not relate to annoyance versus calm.Step 4: Soothing means calming, comforting or reducing pain and irritation, which directly contrasts with causing annoyance.Step 5: Pliable means easily bent or easily influenced, which is unrelated to how irritating or calming something is.Step 6: Hence, Soothing is the best antonym of vexatious among the given options.

Verification / Alternative check:
We can test the words in context. A vexatious noise in the street kept him awake, but a soothing lullaby helped him sleep, shows clear opposition. Vexatious and soothing stand on opposite sides of the comfort scale. Using Calamitous, Treachery or Pliable in that place does not create any natural contrast. Therefore, the pairing vexatious versus soothing makes the most sense for an antonym question.

Why Other Options Are Wrong:
- Calamitous suggests large scale disaster, which is still negative, not opposite to vexatious in the sense of calming or pleasant.
- Treachery deals with betrayal and is a moral term, not simply about irritation or comfort.
- Pliable refers to flexibility or susceptibility to influence, which has no direct connection with the idea of vexing or soothing.

Common Pitfalls:
Test takers sometimes pick another negative word as an antonym simply because the given word feels negative. However, an antonym should reverse the quality, not just differ in direction. For vexatious, the opposite quality is calm or comfort, not a different type of harm like disaster or betrayal. To avoid confusion, always translate the target word into a simple phrase in your mind, such as very annoying, and then look for an option that means the reverse, for example very calming.

Final Answer:
The word that is opposite in meaning to Vexatious is Soothing.