Attain some rare achievements (5)
I believe the answer is:
reach
'attain' is the definition.
(reaching is a kind of attaining)
'some rare achievements' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'REACH' can be found hidden inside 'rare achievements'.
(Other definitions for reach that I've seen before include "Extend an arm" , "Get in touch" , "Come up to - stretch between bends" , "Extent of influence" , "Open stretch of water" .)