Cross sequence of letters from tetchy bridegroom (6)
I believe the answer is:
hybrid
'cross sequence' is the definition.
'hybrid' can be an answer for 'cross' (I've seen this before). I am not sure about the 'sequence' bit.
'letters from tetchy bridegroom' is the wordplay.
'letters from' says the answer is hidden in the clue (a selection of letters from the clue).
'HYBRID' is hidden within 'tetchy bridegroom'.
'of' is the link.
Can you help me to learn more?
(Other definitions for hybrid that I've seen before include "Genetic cross" , "Offspring of mixed parents" , "Plant grown from two different species" , "Cross breed" , "outcome of miscegenation?" .)