mahā-rathāḥ - warriors who could single handedly match the strength of ten thousand ordinary warriors
yeṣhām - for whom
cha - and
tvam - you
bahu-mataḥ - high esteemed
bhūtvā - having been
yāsyasi - you will loose
lāghavam - decreased in value
Translation
The great chariot-warriors will think that you have withdrawn from the battle out of fear, and you will be held in low esteem by those who have held you in high regard.