Leymah is a Kpelle-Liberian feminine name. Leymah Gbowee (born 1972) was the Liberian peace activist who organized the Women of Liberia Mass Action for Peace — a coalition of Christian and Muslim women whose nonviolent protest and sex strike helped end the Second Liberian Civil War (2003).
Leymah does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Leymah reduce to 1, The Leader. This is a traditional interpretive system, not a factual claim about the name.