Describe figurative speech in "The Workbox" by Thomas Hardy.

In this seemingly simple poem about village life, a woodworker or "joiner" gives his wife a wooden sewing box he has made for her. At first, this appears a touching gesture, and the wife approaches the husband with "a smile" and tells him it "Twill last all my sewing years!" The language his conveys happiness.

But then the sweet poem turns dark as the wife learns the box was made of a leftover piece of the coffin of a man, John Wayward, from the wife's village. The husband wonders if she is concerned about having a box made from a coffin, and mentions the idea that the wood stands for the proximity of life and death:

One inch where people eat and drink/the next inch in a tomb.

The wife said that doesn't bother her but she is clearly upset by the gift, leading the reader to suspect that she once was Wayward's lover.

Here are some ways the poem uses figurative language:

First, the word "joiner" is a double entendre. A joiner is a carpenter, but here the "joiner" joins things in other ways. He joins life and death figuratively by literally making the sewing box out of the same wood as a coffin. The wood of the coffin stands for death: the carpenter joins death to the wife's everyday life. He also, through his gift, "joins" his wife to the dead Wayward. 

The poem uses irony. We find out, along with the wife, that what seems like a kind-hearted gift actually carries a zinger: it turns out to be a cruel gift that hurts the wife. We know this because she goes from smiling to "her lips ... limp and wan." There is figurative speech in these words, for we sometimes describe newly dead bodies as "limp and wan" (pale). Rather than giving her life through the gift, the husband has given his wife a taste of death--or at least of illness.

We don't know if John Wayward was the wife's lover or if the husband knows this, but the fact that he wants to inform her of all the morbid details about the box would indicate he does.  

The sewing box becomes a metaphor for death: it is no longer simply a wooden box that holds sewing supplies but the symbol of a dead man.