Which word describes someone who is intrusive in a meddling or offensive manner?

The term that accurately describes someone who is intrusive in a meddling or offensive manner is "officious." This word conveys a sense of someone who is overly eager to offer unwanted help or advice, often stepping beyond acceptable boundaries and being intrusive in the process. An officious person typically imposes their opinions or assistance on others, which can be perceived as meddling and unwelcome.

In contrast, the other options provided do not capture this meaning. "Ostensible" refers to something that is outwardly apparent but may not reflect the true situation, thus lacking the connotation of intrusion. "Maunder" generally means to talk in a rambling or meaningless way, which does not relate to being intrusive. "Macerate," on the other hand, means to soften or break down something (often food) by soaking it in a liquid, and it has no relevance to the social or intrusive behaviors described in the question.