A youth moving to catch knight, then king, cheers
I believe the answer is:
thank you
'king cheers' is the definition.
'thank you' can be an answer for 'cheers' (I've seen this before). I'm not certain of the 'king' bit.
'a youth moving to catch knight' is the wordplay.
'moving' is an anagram indicator.
'to catch' means one lot of letters goes inside another.
'knight' becomes 'ank' (I can't explain this - if you can you should believe this answer much more).
'youth' anagrammed gives 'thyou'.
'thyou' placed around 'ank' is 'THANK-YOU'.
'then' is the link.
Can you help me to learn more?
(Other definitions for thank you that I've seen before include "Cheers" , "Concentional expression of appreciation" , "Polite acknowledgment" , "Polite reply (to gift)" , "I'm grateful" .)