In English vocabulary, select the option that gives the antonym (opposite in meaning) of the word 'frazzle' meaning to exhaust completely.

Introduction / Context:
Antonym questions check whether you can recognise not just the meaning of a word, but also its opposite. The word 'frazzle' is an informal verb and noun that refers to extreme tiredness or to exhausting someone. In exam contexts, 'to frazzle' or 'to be frazzled' usually implies being worn out, mentally or physically. To find the antonym, we must look for a word that conveys energy, strength, or freshness instead of exhaustion.

Given Data / Assumptions:

Target word: 'frazzle' (exhaust, wear out, become extremely tired).
Options: prostration, vigour, enervation, lassitude.
We assume standard dictionary meanings of these words.
We must find the word opposite to tiredness and exhaustion.

Concept / Approach:
'Frazzle' is closely related to being drained of energy. Its synonyms include words like 'exhaustion' and 'weariness'. Therefore, the antonym must represent energy, vitality, or robustness. 'Vigour' is a noun that denotes strength, energy, and enthusiasm. The other options describe different kinds of weakness or tiredness. Thus, even if the words look advanced or formal, the semantic contrast between 'frazzle' and 'vigour' is clear once you understand their meanings.

Step-by-Step Solution:
Step 1: Understand 'frazzle': to exhaust or be in a state of extreme tiredness and mental strain. Step 2: Examine 'prostration': this means extreme physical weakness or lying stretched out, often due to exhaustion or illness. It is similar in meaning to 'frazzle', not opposite. Step 3: Examine 'enervation': it refers to a feeling of being drained of energy, again very similar to frazzled exhaustion. Step 4: Examine 'lassitude': this describes a state of weariness, lack of energy, or fatigue, which aligns with the idea of being frazzled. Step 5: Examine 'vigour': this means physical strength, energy, or enthusiasm, which directly contrasts with exhaustion. Step 6: Conclude that 'vigour' is the correct antonym of 'frazzle'.

Verification / Alternative check:
To verify, imagine converting a sentence from negative to positive. 'After the long journey, she was frazzled' could be contrasted with 'After a good rest, she was full of vigour.' This shows a clear opposite relationship: the first sentence shows extreme tiredness, the second shows abundant energy. The other options—prostration, enervation, and lassitude—could easily replace 'frazzled' to reinforce tiredness, which proves they are synonyms or near-synonyms, not antonyms.

Why Other Options Are Wrong:
'Prostration' emphasises total collapse from exhaustion or illness, which is close in meaning to 'frazzle'. 'Enervation' specifically means a loss of energy and vitality, basically the condition that 'frazzle' creates. 'Lassitude' is another word for weariness or lack of energy. All three describe states of tiredness and weakness. Because antonym questions require a word with the opposite sense, choosing any of these would repeat the same idea rather than give a contrast.

Common Pitfalls:
A common mistake is to assume that the most difficult or least familiar word must be the answer. In this list, 'enervation' and 'lassitude' may look impressive, but they are actually synonyms of 'frazzle'. Another pitfall is not paying attention to parts of speech. All options here are nouns, matching the noun form of 'frazzle' in context, so you cannot eliminate any based on grammar; you must rely purely on meaning. Building a strong vocabulary by learning both synonyms and antonyms together helps you avoid these traps.

Final Answer:
The correct antonym of 'frazzle' is 'vigour'.