out on a limb
US /aʊt ɑn ə lɪm/
UK /aʊt ɑn ə lɪm/
1.
in a dangerous or isolated position where one is dependent on others
:
•
He went out on a limb to support his friend, even though it meant risking his own reputation.
•
If you go out on a limb and make that claim, you'd better have evidence to back it up.