STURDY means strongly and solidly built. 'Robust' is the best synonym, as it also means strong and healthy or strongly built. While a sturdy object might be 'hard,' 'heavy,' or 'large,' these words describe different qualities and are not direct synonyms for being well-built.

To AUTHORIZE is to give official permission for something. 'Permit' means to allow something, which is the best synonym. To 'command' is to give an order, which is different from giving permission. To 'trust' someone is to have confidence in them, which is often why they are authorized, but it's not the same meaning. 'Create' means to bring something into existence.

DENSE means closely compacted or having its parts crowded together. 'Thick' is the best synonym in this context (e.g., a thick forest, a thick fog). A dense forest might be 'dark,' but this is a result of the denseness, not its meaning. Dense objects are often 'heavy' for their size, but density and weight are different concepts. An object can be 'solid' without being dense.

ACCURATE means correct in all details. 'Exact' is the best synonym, meaning not approximated in any way; precise. An 'honest' answer is truthful, but it might not be accurate if the person is mistaken. A 'direct' answer gets straight to the point but could still be wrong. 'Positive' means certain or confident, which does not mean the information is correct.

BRIEF means of short duration or concise. 'Short' is the best synonym. 'Abrupt' implies suddenness and can be perceived as rude, which is different from just being short. A brief statement might be 'simple,' but complex ideas can also be stated briefly. 'Quiet' is unrelated in meaning.

RELUCTANT means hesitant or unwilling to do something. The closest synonym is 'unwilling.' A person might be reluctant because they are 'afraid,' but fear is a cause of reluctance, not the same thing. Reluctance might cause someone to be 'slow,' but that is a result, not the meaning itself. 'Stubborn' means determined not to change one's attitude, which is different from being hesitant.

VAST means of a very great extent or quantity. 'Immense' also means extremely large or great. 'Deep' and 'wide' describe size in only one dimension, whereas vast refers to overall great size. A vast area might be 'empty,' but vastness refers to its size, not its contents.

To MINGLE means to mix or move among and talk to others at a social event. 'Blend' also means to mix smoothly and inseparably together. While people 'gather' or 'join' a group to mingle, these words mean to come together, not necessarily to interact and mix. People may 'share' stories when they mingle, but it is not the same action.

To ALTER something is to change it in some way. 'Modify' is the best synonym, meaning to make partial or minor changes to something. 'Fix' means to repair, which is a specific kind of alteration. 'Remove' and 'switch' are types of changes, but they are more specific and extreme than the general meaning of alter.

To ABANDON is to give up on completely or to cease to support or look after. 'Desert' carries a very similar meaning of leaving someone or something without intending to return. 'Leave' is more general and does not have the same sense of finality. One might 'forget' something they abandoned, but it is not the same action. 'Release' means to set free.