Send value from one to onclick

Your question is a bit confusing but I think that's what you want.

    //HTML
<div id="dicaDiv" class="text-center">
    <p id="pDica1" style="display: inline;">Dica 1: 
        <span id="mostrarDica1">
            <a href="#" onclick="gerarDica('dica1');">mostrar dica</a>
        </span>.
    </p>
    <br>
    <p id="pDica2" style="display: inline;">Dica 2: 
        <span id="MostrarDica2">
            <a href="#" onclick="gerarDica('dica2');">mostrar dica</a>
        </span>.
    </p>
    <br>
</div>

//JS
var dica;
function gerarDica(dica) {
    if(dica == "dica1") {
        if(randomClasse == 0)
            dica = "veículo";
        else if(randomClasse == 1)
            dica = "animal";
        else if(randomClasse == 2)
            dica = "cor";
        document.getElementById("mostrarDica1").innerHTML = dica;
        document.getElementById("botaoDica").style.display = "none";
    }
  }

I suggest using switch when you have more than two chained ifs

function gerarDica(dica) {
    if(dica == "dica1") {
        switch (randomClasse) {
          case 0:
            dica = "veículo";
            break;

          case 1:
            dica = "animal";
            break;

          case 2:
            dica = "cor";
            break;

          default:
            dica ='alguma valor padrao';
            break;
      }
        document.getElementById("mostrarDica1").innerHTML = dica;
        document.getElementById("botaoDica").style.display = "none";
    }
  }

If you want a JavaScript to be executed when clicking a link, do not use href , but onclick .

Other details:

• tag a has no attribute value . So an alternative is to pass the value directly to the function gerarDica
• It is customary to leave href with # and make function call on onclick return false , so that the link do not be followed .

I gave a simplified one in your code so that you only have the relevant parts to the solution of this specific problem, but you can easily adapt it to your code:

function gerarDica(dica) {
    // vou só imprimir o valor para mostrar que está funcionando
    console.log(dica);

    // ... faz tudo que precisa fazer com a dica
  
    // retorna false para o link não ser "seguido"
    return false;
}

<a href="#" onclick="javascript:return gerarDica('dica1');">mostrar dica1</a>
<br>
<a href="#" onclick="javascript:return gerarDica('dica2');">mostrar dica2</a>