Might it give Tabitha heart when horse riding? (5)
I believe the answer is:
habit
'might it give tabitha heart' is the definition.
I can't judge whether this defines the answer.
'when horse riding?' is the wordplay.
'when' becomes 'abit' (I can't justify this - if you can you should believe this answer much more).
'horse' becomes 'H' (abbreviation as in horse power).
'riding?' says to put letters next to each other (in a down clue, some letters go on top of others).
'abit' after 'h' is 'HABIT'.
Can you help me to learn more?
(Other definitions for habit that I've seen before include "Monk's gown or custom" , "Custom, wont" , "Propensity" , "It's worn in order" , "Custom; clothing" .)