@Reconstructo,
Words and their place in language are meaningful because they are common and to the extent they can be shared; you cannot have a private language.
But philosophers wish to present an uncommon or unique perspective about the world; and the more this perspective differs from the ordinary, the more difficult it is to find meaningful expression using words in the normal or common definitions.
Now the poet faces the same problems but stretches words and meanings by employing the techniques of his craft to produce an illusive and highly individual form of communication.
But the philosopher's vision is one that must be articulated and explained through argumentation. To do this, he often either invents new words or uses common words in very specialised senses that redefine them for his audience if they but take the care and time to read him carefully.
Even the Presocratics, in the slow separation of rational thinking from mythology, had begun to employ specialised uses of words---often in a poetical sense---used to descibe concepts: Heraclitos for example, often used war or strife to convey his perspective.
Sokrates was, if Plato's accounts are correct, always concerned that many common words were used without really thinking about what they meant; in searching for better definitions, he was in his own fashion, attempting to clarify and articulate (by rejecting common usage) philosophical concepts.
Plato, resorted to poetical myths (the cave) at times, but also began to use common words with very distinct meanings (the divided line); every schoolboy knows that he used a common Greek word "ideas" to describe the "Forms" in his attempt to provide an account of participation.
Aristotle, in his review of his predecessors in the first book of the Metaphysics, examines the concept of "cause" and finds it had been used (incompletely in his view) in different senses; he then proposed a more complete ("better") definition of cause (or definitions since cause meant four different things).
More recently, it was Hegel who built much of his philosophy on a special definition of "dialectic" as a specific process. Whitehead employed negative and positive prehensions, "occasion" and other specialised words to
redescribe events.