Reserved some bicycles (3)
I believe the answer is:
icy
'reserved' is the definition.
(thesaurus)
'some bicycles' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'ICY' is hidden in the letters of 'bicycles'.
(Other definitions for icy that I've seen before include "Glacial" , "Posing danger on the road" , "Very cold, hostile" , "Distant - freezing" , "(Of relations) very hostile" .)