6 ideas
For a large class of cases, the meaning of a word is its use in the language, not an object it names or a mental image it calls up. To understand a word is to master its role in activities: what moves it licenses, what follows from it, how it is corrected. Asking 'what does this word stand for?' often creates the confusion it tries to solve.
Speaking is part of an activity. Words work inside practices like giving orders, reporting, joking, or building with slabs, and those practices are woven into a shared form of life. Language has no single essence. It is a family of distinct games, each with its own rules and point.
Things called 'games' share no single feature common to all of them. Instead they are linked by a network of overlapping and criss-crossing similarities, like resemblances among family members. A concept can have blurred edges and still be perfectly usable, so demanding a sharp definition before using a word is a mistake.
Any rule can be interpreted to fit any course of action, so no inner interpretation can fix what counts as following it correctly. Following a rule is a trained, public custom: we obey the rule 'blindly', and correctness is anchored in shared practice and agreement in reactions. Thinking you are following a rule is therefore not the same as following it.
Suppose everyone has a box containing something called a 'beetle', but no one can look in anyone else's box. The thing in the box then has no role in the language-game. It could be constantly changing, or the box could be empty. If a sensation word got its meaning from a purely private object, that object would 'drop out of consideration as irrelevant', so meaning must rest on public criteria.
Philosophical problems arise when language 'goes on holiday': words are pulled out of their ordinary use and made to do jobs they never did. The remedy is to lay out how words are actually used until the problem dissolves, not to build new theories. The aim is 'to shew the fly the way out of the fly-bottle'.