supplement, supply, make good, offset, compensate, assistant, learner
補 centers on filling a gap or making up for a deficiency: supplementing what is missing, compensating for a lack, or offsetting a shortfall. The senses of assistant and learner extend from the idea of someone who helps fill a role or knowledge gap.
補 combines 衤 (clothing) with 甫, which likely contributes the sound and the idea of patching or mending cloth. The core notion of supplementing or making good a deficiency extends naturally from repairing garments.
The clothing radical 衤 suggests fabric, and 甫 looks like a patch being sewn on. Picture mending a torn garment by adding a patch to supplement the missing cloth.
For ホ, imagine a hole in your clothes that needs patching: hole -> ホ, and you supplement the fabric to make it whole again.
candidate; contender; prospect; pick; choice; list
assistance; support; help; aid
supply; supplying; replenishment
candidacy; standing as a candidate; bidding (to host an event, e.g. the Olympics)
compensation; reparation
correction; revision; compensation (e.g. to a pendulum)
aid; help; assistance; assistant; counselor; counsellor; adviser; advisor
reinforcement; strengthening
supplement; complement
replenishment; supplementation; supplement; replacement; refilling
complementation; supplementation; completion
to supplement; to make up for; to compensate for; to cover (a shortage, loss, etc.); to fill (e.g. a vacancy)
repair; mending
assistant inspector
covering (a loss, deficit, etc.); making up (for); compensating (for); supplementation
supplementary lessons
filling a vacancy; supplementation
hearing aid
guidance; direction; leading
candidate (for an election)