壁にもたれかかるな。

wall; partition; barrier; obstacle; Chinese "Wall" constellation (one of the 28 mansions)

at (place, time); in; on; during; to (direction, state); toward; into; for (purpose); because of (reason); for; with; by; from; as (i.e. in the role of); per; in; for; a (e.g. "once a month"); and; in addition to; if; although

to lean on; to recline on; to rely on; to depend on

(sentence end, mainly masc.) indicates emotion or emphasis; (used with masu stem verb) command; (used with dictionary form verb) prohibition