Change tack fast, initially willing to wait outside (6)
I believe the answer is:
swerve
'change tack' is the definition.
'swerve' can be an answer for 'tack' (thesaurus). I am unsure of the 'change' bit.
'initially willing to wait outside' is the wordplay.
'initially' indicates taking the first letters.
'to wait' becomes 'serve' (to wait on someone is to serve them).
'outside' is an insertion indicator (some letters go outside others).
The initial letter of 'willing' is 'w'.
'w' going within 'serve' is 'SWERVE'.
'fast' is the link.
Can you help me to learn more?
(Other definitions for swerve that I've seen before include "try to avoid" , "Veer wildly" , "Deviate from the straight path" , "Divergence from course" , "Turn suddenly aside from a straight course" .)