きり

Only
Noun/Counter + きり

きり is the ます stem of きる, to end.
It is a suffixing noun that is used to express “Just/Only some small number”. 
Its basically identical to だけ in this meaning, but has a sense of exclusiveness to it. 
Examples include: “just that one time” or “Just the two of us”.

Examples

• 許すのは今回きりだ
  I’ll forgive you just this once.
  
  
• 二人きりに出掛けよう
  Let’s go out with just the two of us.
  
  
• チャンスは1度きりだ
  You just have one chance.
  
  
• それきり、会っていない
  Since then, I’ve not seen them.*
  
  
• 一度きりのチャンスだ
  A chance you get just once.
  
  

*それきり is an expression using きり, and is not interchangeable with だけ. 
それきり means “Not done since then”. (see below). 

たきり

Not since then
Simple Past Tense Verb + きり

きり may be used with a plain past tense verb to indicate the last time an action was done.
The final verb tends to be present progressive or past tense. 

Examples

• 2－3年前に行ったきり、行っていない
  I went 2 or 3 years ago and haven’t been since.
  
  
• 卒業の祝いで会ったきり、顔を見ていない
  Haven’t seen them since the graduation party.
  
  
• あのアニメは一度見たきりで、名前を忘れた
  I saw that anime only once and forgot its name.