In this case peculiar is closer.
When you say someone is "particolare" you are using an adjective to describe him. You aren't saying he's specific... Would you ever use "particular" to describe a person? :P You are saying he's quite odd.
This is the way "particolare" is used many times.
You can use particular to describe a person, especially if they were fussy about what they wanted to eat, for example.
You would say that they are "particular about what they like to eat". Meaning that they have a very specific (but not necessarily odd) type of food (or style of cooking) that they want. Or even if they only eat fresh food, never frozen, then they they are particular about how the food is served.
In that case, particular is not a good definition for the nuance, as in English one could say - I like that particular type of shoe. Having special and particular as a hint totally threw me off - no way I could foresee that the correct translation is "peculiar." Particular does not mean peculiar. To say "He is particular about whom he dates." is another meaning which implies he is careful about choosing.
In this case perhaps, someone non English speaking created the sentence and hints.
In one instance, "peculiar" does not mean odd: "belonging exclusively to or being specific to one particular entity", as in "The ability to swim in the ocean is peculiar to iguanas in the Galapagos Islands". That is, no other species of iguana anywhere on earth is known to have the ability to swim in the ocean.
Other than that, it means "odd, or strange".
Peculiar note: A "peculiar" (noun) is a parish in England which is not subject to the rule of the diocese where it is located, but is still subject to the rule of the Archbishop of Canterbury and the current monarch of the UK.
According to Merriam -Webster.com:
Particular - A specific among similar items/persons etc, - or somebody (overly) concerned with detail
Peculiar - Different from normal, odd, strange
According to WordReference.com:
Particular = Particolare, specifico, preciso, meticoloso
Peculiar = Strano, bizzaro, originale, particolare, insolito
Pleased to be learning Italian but coming from English, this is a strange translation to me.
And I say this with utmost respect to the "other" language. I think as English has and continues to have such a strong cultural influence, we sometimes forget other languages have different rules etc.
Why should it make sense to a native English speaker.... I put it partly down to the arrogance and aristocratic nature of England lol
As a language teacher, I come up against the word "particular" again and again, loosed translated from the Italian "particolare". There is no easy answer to this one: in Italian, the meaning is often relative, and is anything but precise. Its meaning can change subtly, depending on the context. I would avoid using this word in a phrase out of context. Without the context, you can't really know what a person means, you can only speculate...
Which it does, but not always. =/ Sometimes it means peculiar.
[Edit] Plus links so, should anyone wish, they can look at particolare in various contexts:
John, No. If an auxiliary is used, it results in a compound past tense and you'd use the past participle with it. If you're referring to the given sentence above, you may be confusing the form of the adjective with that of an infinitive. But particolare is an adjective following the verb 'to be'.