Choose the option that best expresses the meaning of the English expression "gate crasher".

Introduction / Context:
This vocabulary question tests your understanding of a specific English expression used in social contexts: gate crasher. It commonly appears in descriptions of parties, functions, or events. Knowing such terms helps you understand everyday conversations and reading passages about gatherings or celebrations.

Given Data / Assumptions:
The expression is:

• gate crasher

The options are:

• Invader
• Thief
• Uninvited guest
• Children

Concept / Approach:
A gate crasher is someone who attends a party, event, or function without having been invited or without a valid ticket or permission. The word does not automatically imply violence or theft; it mainly indicates that the person has entered without authorisation. Therefore the correct option must clearly capture the idea of attending an event without an invitation.

Step-by-Step Solution:
Step 1: Identify the context. Gate crasher is usually used in relation to social or public events. Step 2: Examine Invader. An invader is someone who enters a country or place aggressively, often with armed force. This is too strong and does not match the social tone of gate crasher. Step 3: Examine Thief. A thief is one who steals. Although a gate crasher may or may not steal, stealing is not part of the definition of the term. Step 4: Examine Uninvited guest. This phrase exactly describes someone who appears at a party or event without an invitation. Step 5: Examine Children. This option is clearly unrelated to the basic meaning of gate crasher. Step 6: Therefore, Uninvited guest is the correct answer because it captures the core idea of unauthorised attendance at a social function.

Verification / Alternative check:
Check by forming a sentence: Several gate crashers entered the wedding reception and joined the buffet line. Here, the context suggests that these people were not on the guest list but still entered. The sentence does not state that they invaded the venue with force or that they were stealing anything; it only implies that they attended without being invited. This matches the meaning Uninvited guest.

Why Other Options Are Wrong:
Invader is wrong because it suggests a military or violent entry, which is too extreme for this casual expression. Thief is wrong because gate crashers are not defined by stealing, even if some may behave badly. Children is wrong because age is not part of the meaning. A gate crasher could be of any age group, and the term only refers to the lack of invitation.

Common Pitfalls:
Students sometimes confuse gate crasher with words indicating crime or attack, because the word crash may sound dramatic. However, in social English it is a light expression, not a legal label. Another pitfall is ignoring the typical contexts where you read the word, such as party reports or news about public functions. Observing how the term is used in real examples helps fix its meaning as an uninvited guest rather than an invader or thief.

Final Answer:
The term gate crasher means Uninvited guest.