Yours truly in danger, stupidly going off course (10)
I believe the answer is:
meandering
'going off course' is the definition.
'meandering' can be an answer for 'going' (meandering is a kind of going). I'm unsure of the 'off course' bit.
'yours truly in danger stupidly' is the wordplay.
'yours truly' becomes 'me' (the person who set this crossword).
'stupidly' is an anagram indicator (a stupid ordering of the letters).
'in'+'danger'='indanger'
'indanger' is an anagram of 'andering'.
'me'+'andering'='MEANDERING'
Can you help me to learn more?
(Other definitions for meandering that I've seen before include "full of twists and turns" , "convoluted" , "Winding, rambling" , "not in straight line" , "not proceeding directly" .)