Since A Midsummer Night's Dream was written, many words in English have changed their meaning, and some are no longer used. If you remember the slang you used a few years ago, it seems dated. Who now uses the word "groovy"? Shakespeare used the rich vocabulary of his day within his plays. When reading Shakespeare, you should read the line in context of the scene. Try translating the lines into your own words; use today's vernacular.
Immediately: expressly, explicitly
"As she is mine, I may dispose of her;
Which shall be either to this gentleman,
Or to her death, according to our law
Immediately provided in that case."
"You can endure the livery of a nun,
For aye to be in shady cloister mew'd
To live a barren sister all your life."
— Theseus (1.1.70–72)
Lodestars: guiding stars
Air: melody, music
"Your eyes are loadstars, and your tongue's sweet air
More tuneable than lark to shepherd's ear."
That's all one: that makes no difference
"That's all one"
Obscenely: Bottom may connect this word with seen and mean 'without being observed,' or with scene and mean 'dramatically'
"We will meet, and there we may rehearse most obscenely."
Orbs: fairy rings, circles of darker grass
"I serve the Fairy Queen,
To dew her orbs upon the green."
Dewlop: fold of skin on the throat
"And when she drinks, against her lips I bob,
And on her withered dewlop pour the ale."
Leviathan: gigantic sea-beast, usually identified with the whale
"Fetch me this herb, and be thou here again
Ere the leviathan can swim a league."
Apollo flies, and Daphne holds the chase: according to the myth, Daphne, pursued by Apollo, was saved from rape by being transformed into a laurel tree
Griffin: fabulous monster with the body of a lion and the head of an eagle
Hind: female red deer
Bootless: useless, futile
"The wildest hath not such a heart as you.
Run when you will; the story shall be chang'd:
Apollo flies, and Daphne holds the chase
The dove pursues the griffin; the mild hind
Makes speed to catch the tiger—bootless speed,
When cowardice pursues and valor flies."
Aby: pay for, atone for
"Disparage not the faith thou dost not know,
Lest, to thy peril, thou aby it dear."
Curst: quarrelsome, shrewish, sharp-tongued
"I was never curst;
I have no gift at all in shrewishness."
Favors: flowers as love gifts
"Seeking sweet favors."
Fairy Toys: trifling tales about fairy doings
"More strange than true. I never may believe
These antic fables, nor these fairy toys."
In addition, Shakespeare uses figurative language as he speaks with metaphors, similes, and personification. Recognizing when his characters are speaking figuratively helps in understanding the play.
A metaphor is the application of a word or phrase to somebody or something that is not meant literally but to make a comparison. For example: Lysander compares Hermia's cheeks to roses. She then replies comparing her tears to rain.
Lysander: Why is your cheek so pale?
How chance the roses there do fade so fast?
Hermia: Belike for want of rain, which I could well
Beteem them from the tempest of my eyes (1.1.128–131).
A simile is a figure of speech that draws comparison between two different things using the word "like" or "as." For example: Lysander compares choice to numerous momentary events.
"Or if there were any sympathy in choice,
War, death, or sickness did lay siege to it,
Making it momentary as a sound,
Swift as a shadow, short as any dream,
Brief as the lightning in the collied night,
That in a spleen, unfolds both heaven and earth" (1.1.141–146).
Personification occurs when human attributes or qualities are applied to objects or abstract notions. For example: Lysander eludes to the law chasing after he and Hermia.
"There, gentle Hermia, may I marry thee,
And to that place the sharp Athenian law
Cannot pursue us" (1.1.161–163).