A dictionary doesn't define what a community is about, and more importantly, it doesn't it redefine the purpose and type of content for which Stack Exchange was created. Stack Exchange was designed with a very specific focus in mind, somewhat different than a typical discussion forum. Sites center on a quantifiable, specific area of expertise by asking ...
Answers are neither on- nor off-topic. They are just answers.
Given they aren't falling into any of the flaggable/deletable categories (spam, offensive, not an answer, etc.) they are just good or bad answers.
And there already is a way to show whether an answer is good or bad: Votes.
That being said: downvote bad (not lifehack) answers and leave them at ...
Although I've done this myself, you have a valid point. Although I have these things sitting around, they were manufactured for the purpose, and so aren't really hacks. They are the regular solution. We could define tool/product/device as:
a device or implement, especially one held in the hand, used to carry out a particular function
A strategy or technique adopted in order to manage one's time and daily activities in a more efficient way.
That's just a tip or a way of doing things. Not everything is a hack. Using the term hack implies an unexpected, innovative, or improvised workaround, often ugly but nevertheless effective.