Pronunciation guide: IPA symbols, stress and word endings

θ	thin	ð	this	ʃ	she	ʒ	measure
tʃ	church	dʒ	judge	ŋ	sing	j	yes

p b t d k g f v s z h m n l r w sound as in ordinary English spelling.

ˈ main stress, before the stressed syllable: /ˈwɔːtə/ water · ˌ lighter (secondary) stress: /ˌʌndəˈstænd/ understand
ː a long vowel · (r) an r said only in accents that pronounce it (most American, Scottish, Irish)

-s / -es (plurals; he/she form of verbs): /s/ after voiceless sounds (cats), /z/ after voiced (dogs), /ɪz/ after s, z, sh, ch, j sounds (buses, watches). Spelling: -es after s, x, z, ch, sh; consonant + y → -ies (city → cities).
-ed (past): /t/ after voiceless sounds (walked), /d/ after voiced (played), /ɪd/ after t or d (wanted). Spelling: love → loved, stop → stopped, carry → carried.
-ing: make → making, run → running, see → seeing.
Irregular: go, went, gone · be, was, been · see, saw, seen · man → men · child → children · mouse → mice.
Older (King James) forms: -eth = -s (he loveth = he loves) · -est with “thou” (thou lovest) · spake = spoke.

look up

/ˌlʊk ˈʌp/ verb

Forms looks up looking up looked up

verb Used other than figuratively or idiomatically: see look, up. “We stayed up late to look up at the stars.”
verb (intransitive, idiomatic) To have better prospects. “Things started looking up after Jim moved back in with his parents.”
verb (transitive, idiomatic) To obtain, or seek to obtain, information about something.
verb To obtain information about something from a reference book. “I didn't know what a mitochondrion was until I looked it up in a dictionary.”
verb To enter a query into a database or search engine. “If you look up a bunch of random characters, there will probably be no results.”
verb (transitive, idiomatic) To reconnect or meet with someone that one used to know.

Synonyms

Sources: Wiktionary · WordNet 3.0 — from the Wiktionary entry “look up”, CC BY-SA 4.0. Details