In A Midsummer Night's Dream, Puck is called a hobgoblin, yet can he be classified as a mischievous fairy?

Puck is called many things in this play.  The reference to
"Hobgoblin" comes in Act II, scene i, when Puck meets one of Titania's fairies in a spot
that both Titania and Oberon are claiming possession of.  This fairy does not seem to be
very friendly to Puck, so the words that he/she speaks against Puck are simply this one
character's opinion, but also reflect the mercurial nature of who and what, exactly,
Puck is.

Here's the text spoken by the First Fairy,
abridged to show the different names used to refer to
Puck:

Either
I mistake your shape and making quite,

Or else you are
that shrewd and knavish
sprite

Called Robin
Goodfellow. . . .

Those that
"Hobgoblin" call you, and "sweet
Puck"...

This
fairy, even though he/she is not on Oberon's team, and as Titania's fairy has no reason
to particularly like Puck, calls him "shrewd," "knavish," a "sprite," "Hobgoblin," and
"sweet Puck," all which conjure up some different
images.

Certainly Puck admits in his next speech to being
mischievous (as you describe him).  Puck says:

readability="7">

I am that merry wanderer of the
night.

I jest to Oberon and make him
smile...

Puck goes on to
describe some of the tricks he has played on unsuspecting humans.  So, yes, certainly,
among other things, Puck can be considered a mischievous
fairy.

For more about Puck and the fairy world of
Shakespeare's s day, please see the links below.