It depends on what "it" is,

For example, if "it" is "the date of the next meeting", then "fix it" must mean "don't change it anymore", since the repair meaning doesn't make sense.

On the other hand, if "it" is "a bicycle", then "fix it" must mean "repair it", because nobody wants their bicycle affixed to something.

There is rarely any confusion, unless done deliberately as a joke. When speaking of things that should not move, then "fix" means "prevent from moving". When speaking of things that should move then fix means "repair".

position:static;, position:absolute;, and position:relative; are the alternatives to position:fixed;. There isn't a definitive opposite, because relative, absolute, static, and fixed have different properties to behave differently.

Take a look at this article:

http://css-tricks.com/absolute-relative-fixed-positioining-how-do-they-differ/

Hint: We need to find the antonym of the word fixed. Read the question and try to understand the context, it will give you an idea about the meaning of the given word. Now go through the options and recall their meaning. The one opposite to the meaning of fixed is the answer.Complete answer: An antonym or an opposite refers to a word that is contrary in meaning to another word. For example- Rebuke is an antonym for praise.‘Fixed’ refers to something pre-determined or pre-arranged. The word ‘fixed’ has been derived from the Latin word- Fixus, which means to fasten or fix.We know the meaning and the origin of the word ‘fixed’. Now, let’s look at its usage:For example- My bank only provides loans for a fixed period. Here, we can conclude that X’s bank only provides loans for a pre-determined or allotted period.Let’s decipher the meaning of the given options-Option a- ‘Affixed’ refers to attaching or securing to something else. For example- The lawyer advised us to affix a copy of our signatures on the sheet. ‘Affixed’ is different in meaning to the given context. Hence, it is an incorrect option.Option b- ‘Scheduled’ refers to something that is planned or pre-destined to happen. For example- Our teacher scheduled an extra-class. ‘Scheduled’ is different in meaning to the given context. Hence, it is an incorrect option.Option c- ‘Flexible’ refers to something that can be adjusted or adapted. For example- Mother told me to be flexible about my options. ‘Flexible’ is opposite in meaning to the given context. Hence, it is the correct option.Option d- ‘Attached’ refers to connected or joined to something. For example- He attached the documents with the sheet. ‘Attached’ is different in meaning to the given context. Hence, it is an incorrect option. The correct answer is Option ‘c’.Note: Some other antonyms for ‘fixed’ are; indefinite, insecure, undecided, etc while some synonyms for ‘fixed’ are- established, immovable, rigid, etc.