Possible Clues:

• Lacking balance
• Giving up weed and stout maybe a reason one fell over
• Humpty-Dumpty, for one, with head on stout
• Likely to fall over
• Likely to tip over
• Unbalanced
• Spinner overweight, likely to fall over
• Unstable through being over-loaded at the higher end
• Likely to fall from summit? Serious
• Having the upper part too large for the lower