The verb ‘to lump’ means ‘to put up with ungraciously’. This is the answer to anyone who complains about something that is unavoidable.
‘We’ve missed the last bus, so we’ll have to walk home.’
‘You don’t expect me to tramp three miles in the rain, do you?’
‘There’s no help for it. It’s the only way of getting home, and if you don’t like it you can lump it.’