Conversations, idioms/phrases

Hugmynd - idea
Geta - ability
Lesa - read
Þetta - this
Duglegur - hardworking, efficient
Vakna - awaken, wake up
Hálf - half
Djöfull - Devil
Þreyttur - tired, exhaused
Gerður - made
Biða - wait
Þurfa - need, require, have to
Gá - look, check
Hvort - if, whether
Kannski - maybe
Kenna - teach
Skrift - writing, handwriting
Uppskrift - recipe
Frábær - distinguished, excellent
Jökulhlaup - run-off from a sub-glacial eruption, debacle
Sigti - colander, sieve, strainer
Næturvakt - Night shift
Töffari - tough guy, someone who acts cool
Bíddu aðeins, bíddu smá - wait a little
Ógeðslega - disgustingly (used for emphasis, equivalent to "really")
Ógeðslega flottür - really cool
Ógeðslega gaman - really fun
Ógeðslega ertu leiðinlegur - You're really mean
Þetta er leiðinlegt - This is not fun, this is boring
Þú ert leiðinlegur - You're not fun, you're mean
Vorboð - hint of spring
Svefngalsi - sleep exuberance (When you've had little sleep and become suddenly silly and energetic before you crash.)
Hvað meinarðu? (pronounced "hva meinaru") - What do you mean?
Vigur (from poetry) = spjót (spear, javelin)

Conversations:
Geturu lesið þetta? - (Can you read this?)
Dugleg þú! - (You're hardworking!)
Í dag vaknaði ég klukkan hálf sjö. (Today I woke up at half past six.)
Djöfullinn er ég þreytt! (Damn am I tired!)
Þú gerðir það - (You made it)
Bíddu þarf að gá hvort þetta sé really the real deal. (Must wait to see if this is really the real deal.)
Kannski kann hann ekki að kenna... - (Maybe he can't teach...)
Hvað segir hann gott? - (How is he doing?)
Alexander er frábær leikmaður - (Alexander is an excellent player.)

Idioms and phrases:
Það er eins og þú hafir étið óðs manns skít - It's like you ate a mad man's shit ("Used to describe someone acting like a crazy bitch.")
Líkur sækir líkan heim - Similar pays visit to similar (It takes one to know one)
Sannleikurinn er lyginni líkastur - The truth sounds more like a lie (fact is stranger than fiction)
Samkjafta ekki - To talk nineteen to the dozen (often used sarcastically to comment that someone is being quiet or unresponsive)
Elskið friðinn og strjúkið kviðinn - Love peace and stroke your belly

The words are all from conversations.