Learn Italian: Non intendevo questo: è un malinteso. - I did not mean this: it is a misunderstanding.

To emphasize that you really didn't mean this, you can add mica. You can place it right after the verb: Non intendevo mica questo. Alternatively, you can drop the non and put mica at the very beginning: Mica intendevo questo. Both mean 'I didn't mean this at all!'

Doesn't 'intendere' mean 'to intend'? Why is it translated as 'to mean' here?

Intendere is a partial false friend. While it can mean 'to intend' (like planning to do something), it is very often used to express 'to mean' or 'to understand' a concept. Here, Non intendevo questo simply means 'I did not mean this' or 'That is not what I meant.'

Why use the imperfect tense (intendevo) instead of the passato prossimo (ho inteso)?

The imperfect is used because your intention or meaning was an ongoing state of mind in the past, not a sudden, completed action. When describing what you were thinking or what you meant during a past conversation, the imperfect is the natural choice.

Is the word 'malinteso' related to the verb 'intendere'?

Yes! Malinteso is a compound noun made of male (badly) and inteso (the past participle of intendere, meaning understood). So it literally means 'badly understood,' which makes perfect sense for a misunderstanding.