Slow and reliable taking time (6)
I believe the answer is:
stolid
'slow' is the definition.
(thesaurus)
'reliable taking time' is the wordplay.
'reliable' becomes 'solid' (I've seen this before**).
'taking' indicates putting letters inside.
'time' becomes 't'.
'solid' placed around 't' is 'STOLID'.
'and' is the link.
(Other definitions for stolid that I've seen before include "Wooden" , "Hard to move" , "'Calm and dependable, showing little emotion (6)'" , "Hard to excite" , "Unemotional - dense" .)