Explanation:

The odd pair of words in this question is "Rust : Crest".

Rust is a type of corrosion that occurs on iron or steel when it is exposed to moisture and oxygen over time. It is a natural process that causes the metal to deteriorate and weaken.

Crest, on the other hand, refers to the top or highest point of something, such as a hill or a wave. It can also refer to a decorative emblem or design at the top of a coat of arms or a helmet.

Rust and Crest do not have any significant relationship or similarity in terms of meaning or concept. Rust is related to corrosion and deterioration, while Crest is related to the top or highest point of something. Therefore, they form an odd pair of words in this question.

The other word pairs can be explained as follows:

Honey : Money
Honey is a sweet, sticky substance produced by bees from flower nectar. It is commonly used as a natural sweetener and as an ingredient in various food and beverages. Money, on the other hand, refers to currency or any form of payment that is used to buy goods and services. Honey and money are both related to value or worth, as honey can be sold and money can be used to purchase honey or other items. Therefore, honey and money form a logical and related pair of words.

Nine : Twine
Nine is a number that comes after eight and before ten. It is a numerical value used in counting and mathematics. Twine, on the other hand, refers to a strong string or thread made of two or more strands twisted together. While nine and twine do not have any direct relationship in terms of meaning or concept, they both have the same ending sound "-ine." Therefore, nine and twine form a phonetic pair of words.

Fire : Liar
Fire is a chemical reaction that produces heat, light, and flames. It is commonly used for cooking, heating, and other purposes. Liar, on the other hand, refers to a person who tells lies or falsehoods. While fire and liar do not have any direct relationship in terms of meaning or concept, they both have the same ending sound "-ire." Therefore, fire and liar form a phonetic pair of words.