Select the synonym (word closest in meaning) of "incursion".

Introduction / Context:
This vocabulary question asks you to choose the synonym of the word "incursion". Synonym questions test your ability to identify words with similar meanings and to distinguish between related terms that belong to different semantic fields. "Incursion" is often used in political, military, or territorial contexts, so you must keep that usage in mind when choosing the closest meaning.

Given Data / Assumptions:

• Target word: "incursion".
• Options: hurt, retreat, aggression, cut.
• You must find the option whose meaning is closest to "incursion".

Concept / Approach:
The word "incursion" typically means a sudden or brief invasion or attack into another territory, organisation, or domain. It carries the idea of entering into someone else's space, usually with hostile intent. Therefore, the correct synonym should relate to invasion, attack, or hostile entry, rather than withdrawal or physical injury.

Step-by-Step Solution:
Step 1: Recall that "incursion" often appears in phrases like "military incursion" or "cross-border incursion". Step 2: Examine "hurt". This word refers to injury or pain, usually suffered by a person. It does not capture the idea of invasion or entering another's territory. Step 3: Examine "retreat". This is almost the opposite idea: moving back or withdrawing from a position, especially in battle. Step 4: Examine "aggression". Aggression refers to hostile or attacking behaviour, especially in warfare or conflict, which matches the hostile aspect of an incursion. Step 5: Examine "cut". This usually refers to dividing or reducing something and does not relate to invading territory. Step 6: Conclude that "aggression" is the closest in meaning to "incursion" because both involve hostile action.

Verification / Alternative check:
Consider an example: "The neighbouring country launched an incursion across the border." Replacing "incursion" with "aggression" gives "The neighbouring country launched an aggression across the border," which still conveys hostile action, though we would usually say "act of aggression". This parallel confirms the similarity in meaning. The other options do not fit naturally in such sentences, verifying that "aggression" is the best synonym.

Why Other Options Are Wrong:
"Hurt" focuses on the result of harm to a person or object, not on the act of invading or attacking an area. "Retreat" is a withdrawal, which is the opposite direction of an incursion, where forces move in. "Cut" is related to physical division or reduction in quantity and bears no relation to aggressive entry.

Common Pitfalls:
Students sometimes confuse "incursion" with "injury" because both may appear in news reports about conflicts. However, "incursion" describes the act of entering another area, while "injury" and "hurt" describe damage suffered. Always focus on the core meaning and typical collocations of the word. Learning a few sample phrases such as "armed incursion", "border incursion", and "enemy incursion" can help fix the meaning in memory.

Final Answer:
The synonym of "incursion" is aggression.