Ignoranti quem portum petat, nullus suus ventus est

The Stoic philosopher Seneca the Younger advises us that for the man who doesn't know which port he is making for, no wind is the right one. In other words, if you don't have an objective, you can't reach it. The idea of the modern English proverb - to fail to plan is to plan to fail - is not entirely unrelated.

Ignoranti is the dative singular of the adjective ignorans and means for the ignorant.

Quem is the masculine accusative singular of the relative pronoun qui, quae, quod.

Portum is the accusative singular of the noun portus, -us m a port, from which we get the English word port.

Petat is the third person singular present subjunctive of the third conjugation verb peto, petere, petivi, petitum, meaning among other things to make for.

Ventus, -i m wind is cognate with the French word le vent, the Spanish el viento and the English wind.