Idea, given time, works (5)
I believe the answer is:
plant
'works' is the definition.
(synonyms)
'idea given time' is the wordplay.
'idea' becomes 'plan' (plan is a kind of idea).
'given' says to put letters next to each other.
'time' becomes 't' (abbreviation).
'plan'+'t'='PLANT'
(Other definitions for plant that I've seen before include "Place in the ground to grow" , "Living organism without locomotion" , "eg Flower" , "Hide incriminating evidence" , "Factory equipment" .)