Synonyms and related words :
accelerate, add, adjoin, affix, agglutinate, aggravate, annex, append, attach, ball up, beef up, blow up, burden, concentrate, condense, confound, confuse, conjoin, consolidate, decorate, deepen, derange, disarrange, disorder, double, embrangle, encumber, enhance, entangle, exacerbate, exaggerate, foul up, garble, glue on, heat up, heighten, hitch on, hop up, hot up, implicate, infix, intensify, involve, jazz up, join with, jumble, key up, knot, louse up, magnify, make complex, make unintelligible, mess up, mix up, muck, muck up, muddle, mystify, obfuscate, obscure, ornament, paste on, perplex, plus, postfix, prefix, put with, ramify, ravel, redouble, reinforce, saddle with, scramble, screw up, shadow, sharpen, slap on, snafu, snarl, snarl up, soup up, step up, strengthen, subjoin, suffix, superadd, superpose, tack on, tag, tag on, tangle, triple, unite with, upset, whet